Update MH-E's documentation about HTML renderers

* doc/misc/mh-e.texi (HTML): Remove the footnote with the minimum Gnus
version (we are no longer trying to support multiple Emacs
releases). Sort the table of HTML renderers by name (the previous
ordering was based on a 10-year-old survey). Add shr and gnus-w3m to
the table. Remove the entry for w3 (no longer available).  Update
existing entries so that they are more consistent about what features
are discussed, and to reflect recent testing (Debian 8). Small tweaks
to existing text.

1 files changed, 81 insertions, 60 deletions

diff --git a/doc/misc/mh-e.texi b/doc/misc/mh-e.texi
index c48e4a40ea..795f5c3371 100644
--- a/doc/misc/mh-e.texi
+++ b/doc/misc/mh-e.texi
@@ -2527,8 +2527,7 @@ in the @cite{The Gnus Manual}.
 @cindex HTML
 @cindex Gnus
 
-MH-E can display messages that have been sent in HTML@footnote{This
-feature depends on a version of Gnus that is at least 5.10.}. The
+MH-E can display messages that have been sent in HTML. The
 content of the message will appear in the MH-Show buffer as you would
 expect if the entire message is HTML, or there is an inline HTML body
 part. However, if there is an HTML body part that is an attachment,
@@ -2549,86 +2548,107 @@ based upon the presence of a known browser on your system. If you wish
 to use a different browser, then set this option accordingly. See the
 documentation for the browser you use for additional information on
 how to use it. In particular, find and disable the option to render
-images as this can tip off spammers that the email address they have
-used is valid.
+images, as displaying remote images can tip off spammers that the
+email address they have used is valid.
 
 @vindex mm-text-html-renderer
 
 If you're confused about which @code{mm-text-html-renderer} to use,
-here's a brief description of each, sorted by popularity, that
-includes the results of a quick poll of MH-E users from 2005-12-23.
+here's a brief description of each, sorted by name.
 
 @table @asis
+@cindex browser, @samp{gnus-w3m}
+@cindex @samp{gnus-w3m}
 @cindex browser, @samp{w3m}
 @cindex @samp{w3m}
-@kindex mouse-2
-@item @samp{w3m} 7
-The @samp{w3m} browser requires an external program. It's quick,
-produces pretty nice output, and best of all, it's the only browser
-that highlights links. These can be clicked with @kbd{mouse-2} to view
-the content of the link in @samp{w3m}. The @samp{w3m} browser handles
-tables well and actually respects the table's width parameter (which
-can cause text to wrap if the author didn't anticipate that the page
-would be viewed in Emacs).
+@item @samp{gnus-w3m}
+The @samp{gnus-w3m} browser requires an external program. It's quick,
+produces pretty nice output, and it highlights links. It renders
+@samp{–} and @samp{®} okay. It sometimes fails to wrap lines
+properly. It always downloads remote images.
 @c -------------------------
-@cindex browser, @samp{w3m-standalone}
-@cindex @samp{w3m-standalone}
-@item @samp{w3m-standalone} 3
-This browser, along with @samp{nil} for the external browser, are the
-only choices that work without having to download a separate lisp
-package or external program. This browser is quick, but does not show
-links. It handles simple tables but some tables get rendered much
-wider than the Emacs frame. This browser was the only one not to
-handle the escape @samp{–} (it printed a @samp{?}), but it did
-render @samp{®}.
+@cindex browser, @samp{html2text}
+@cindex @samp{html2text}
+@item @samp{html2text}
+The @samp{html2text} browser requires an external program. Some users
+have reported problems with it, such as filling the entire message as
+if it were one paragraph, or displaying chunks of raw HTML.
 @c -------------------------
 @cindex browser, @samp{links}
 @cindex @samp{links}
-@item @samp{links} 1
+@item @samp{links}
 The @samp{links} browser requires an external program. It's quick, and
 produces nicer output than @samp{lynx} on single column mails in
 tables. However, it doesn't show links and it doesn't do as nice a job
-on multi-column tables as some lines wrap. At least it fits in 80
-columns and thus seems better than @samp{w3} and
-@samp{w3m-standalone}. Converts escapes such as @samp{®} to (R).
+on multi-column tables as some lines wrap. It does do a good job of
+fitting text within 80 columns. It appears to render special
+characters using ASCII equivalents. For example, @samp{®} appears
+as (R). It does not download images.
 @c -------------------------
 @cindex browser, @samp{lynx}
 @cindex @samp{lynx}
-@item @samp{lynx} 1
+@item @samp{lynx}
 The @samp{lynx} browser requires an external program. It's quick and
 produces pretty decent output but it doesn't show links. It doesn't
 seem to do multi-column tables which makes output much cleaner. It
-centers the output and wraps long lines more than most. Handles
-@samp{®}.
+centers the output and wraps long lines more than most. It does not
+always handle special characters like @samp{®} or @samp{–}.
+It does not download images.
 @c -------------------------
-@item @samp{nil} 1
-This choice obviously requires an external browser. Like
-@samp{w3m-standalone}, it works out of the box. With this setting,
+@item @samp{nil}
+This choice obviously requires an external browser. With this setting,
 HTML messages have a button for the body part which you can view with
-@kbd{K v} (@code{mh-folder-toggle-mime-part}).
-@c -------------------------
-@cindex browser, @samp{w3}
-@cindex @samp{w3}
-@item @samp{w3} 0
-This choice does not require an external program as all of the
-rendering is done in lisp. You do need to get the package separately.
-This browser is @strong{slow}, and doesn't appear to have been updated
-since 2001 and the author hasn't responded to my emails. It displays
-unknown tags instead of hiding them, so you get to see all the
-Microsoft crap in certain messages. Tends to make multi-column tables
-wider than even a full-screen Emacs can handle. Like @samp{w3m}, you
-can follow links, but you have to find them first as they are not
-highlighted. Performs well on single-column tables and handles escapes
-such as @samp{®}.
+@kbd{K v} (@code{mh-folder-toggle-mime-part}). Rendering of special
+characters and handling of remote images depends on your choice of
+browser.
+@c -------------------------
+@item @samp{shr}
+@cindex @samp{shr}
+This choice does not require an external program, but it does require
+that Emacs be configured at build time to use @samp{libxml2}. It is
+fairly quick, it highlights links, and it supports HTML color
+declarations. It renders @samp{–} and @samp{®} okay. It
+sometimes truncates text, particularly if the message tries to have
+fancy text layout. By default it does not download images; this
+behavior is controlled by the options @code{mm-html-blocked-images}
+and @code{mm-html-inhibit-images}
+@ifinfo
+(@pxref{Display Customization,,,emacs-mime}).
+@end ifinfo
+@ifnotinfo
+(see section @uref{http://www.gnus.org/manual/emacs-mime_6.html,
+Display Customization} in the @cite{The Emacs MIME Manual}).
+@end ifnotinfo
 @c -------------------------
-@cindex browser, @samp{html2text}
-@cindex @samp{html2text}
-@item @samp{html2text} 0
-The @samp{html2text} browser requires an external program. I noticed
-that it can do some nasty things with simple HTML mails (like filling
-the entire message as if it were one paragraph, including signature).
-On another message, it displayed half of the HTML tags for some
-reason.
+@cindex browser, @samp{w3m}
+@cindex @samp{w3m}
+@kindex mouse-2
+@item @samp{w3m}
+The @samp{w3m} browser requires an external program. It's quick,
+produces pretty nice output, and it highlights links. These can be
+clicked with @kbd{mouse-2} to view the content of the link in
+@samp{w3m}. The @samp{w3m} browser handles tables well and actually
+respects the table's width parameter (which can cause text to wrap if
+the author didn't anticipate that the page would be viewed in Emacs).
+It does not download images by default; this behavior is controlled by
+the option @code{mm-w3m-safe-url-regexp}
+@ifinfo
+(@pxref{Display Customization,,,emacs-mime}).
+@end ifinfo
+@ifnotinfo
+(see section @uref{http://www.gnus.org/manual/emacs-mime_6.html,
+Display Customization} in the @cite{The Emacs MIME Manual}).
+@end ifnotinfo
+@c -------------------------
+@cindex browser, @samp{w3m-standalone}
+@cindex @samp{w3m-standalone}
+@cindex browser, @samp{w3m}
+@cindex @samp{w3m}
+@item @samp{w3m-standalone}
+This browser is quick, but does not show links. It handles simple
+tables but some tables get rendered much wider than the Emacs frame.
+This browser renders @samp{–} and @samp{®} okay. It does not
+download images.
 @end table
 
 @vindex mm-text-html-renderer
@@ -2637,13 +2657,14 @@ For a couple more sources of information about
 @code{mm-text-html-renderer},
 @ifinfo
 @xref{Display Customization,,,emacs-mime}, and the documentation for
-the Gnus command @kbd{W h} (@pxref{Article Washing,,,gnus},).
+the Gnus command @kbd{W h} (@pxref{Article Washing,,,gnus}).
 @end ifinfo
 @ifnotinfo
 see section @uref{http://www.gnus.org/manual/emacs-mime_6.html,
 Display Customization} in the @cite{The Emacs MIME Manual} and the
 documentation for the Gnus command @kbd{W h} (see section
-@uref{http://www.gnus.org/manual/gnus_99.html, Article Washing} in the
+@uref{http://www.gnus.org/manual/gnus_48.html#Article-Washing, Article
+Washing} in the
 @cite{The Gnus Manual}).
 @end ifnotinfo