Enable browse-url to buttonize buffers

This patch also moves the internal/external browser logic from
shr to browse-url, where it belongs more naturally.

* doc/misc/eww.texi (Basics): Adjust to browse-url-external-browser.

* doc/misc/gnus.texi (Article Commands): Ditto.

* lisp/gnus/gnus-art.el (gnus-button-url-regexp): Default to
`browse-url-button-regexp', which has taken over the definition
previously enjoyed by this variable.

* lisp/gnus/gnus-sum.el (gnus-summary-browse-url): Adjust usage.

* lisp/net/browse-url.el (browse-url--browser-defcustom-type): New
internal variable...
(browse-url-browser-function, browse-url-external-browser): Used
by these two; the latter of which is a new variable.
(browse-url-botton-regexp): New variable.
(browse-url-button-map): New keymap.
(browse-url-button): New face.
(browse-url-add-buttons): New function to add clickable browse-url
buttons to almost any buffer.
(browse-url-button-open): New command.
(browse-url-button-copy): New command.

* lisp/net/eww.el (eww-browse-with-external-browser)
(eww-follow-link): Adjust usage.

* lisp/net/shr.el (shr-external-browser): Make an obsolete alias
of `browse-url-external-browser'.
(shr-browse-url): Adjust usage.

2 files changed, 3 insertions, 3 deletions

diff --git a/doc/misc/eww.texi b/doc/misc/eww.texi
index 8dc58e84257..cd74aa32c77 100644
--- a/doc/misc/eww.texi
+++ b/doc/misc/eww.texi
@@ -187,7 +187,7 @@ switch EWW buffers through a minibuffer prompt, press @kbd{s}
 (@code{eww-switch-to-buffer}).
 
 @findex eww-browse-with-external-browser
-@vindex shr-external-browser
+@vindex browse-url-external-browser
 @vindex eww-use-external-browser-for-content-type
 @kindex &
 @cindex External Browser
@@ -197,7 +197,7 @@ or are not implemented (E.g., JavaScript).  If you have trouble
 viewing a website with EWW then hit @kbd{&}
 (@code{eww-browse-with-external-browser}) inside the EWW buffer to
 open the website in the external browser specified by
-@code{shr-external-browser}.  Some content types, such as video or
+@code{browse-url-external-browser}.  Some content types, such as video or
 audio content, do not make sense to display in GNU Emacs at all.  You
 can tell EWW to open specific content automatically in an external
 browser by customizing
diff --git a/doc/misc/gnus.texi b/doc/misc/gnus.texi
index 3968fa58377..7a3322d9fc0 100644
--- a/doc/misc/gnus.texi
+++ b/doc/misc/gnus.texi
@@ -10164,7 +10164,7 @@ do so.
 @findex gnus-summary-browse-url
 Scan the article buffer for links, and offer them to the user for
 browsing with @code{browse-url}.  With a prefix argument, browse with
-@code{shr-external-browser} instead.
+@code{browse-url-external-browser} instead.
 
 @end table