Merge diff-font-lock-refine and diff-auto-refine-mode into diff-refine

This change was discussed in Bug#32991.

* admin/gitmerge.el (gitmerge-resolve): Bind 'diff-refine'
instead of 'diff-auto-refine-mode' to nil.
* doc/emacs/files.texi (Diff Mode): Explain 'diff-refine'
instead of 'diff-auto-refine-mode' in the documentation of
'diff-hunk-next' and 'diff-hunk-prev'.  Mention in the
documentation of 'diff-refine-hunk' that refining is already
done by default.
* etc/NEWS (Diff mode): Explain renamed 'diff-refine' variable
and mention deprecation and disabling of
'diff-auto-refine-mode'.
* lisp/vc/diff-mode.el (diff-font-lock-refine): Rename to
'diff-refine' and allow choices nil, 'font-lock' and 'navigation'.
(diff-auto-refine-mode): Disable it by default, make it
obsolete and make it set 'diff-refine' appropriately to keep
backward compatibility.
(diff-hunk-next, diff-hunk-prev): Adapt to rename of
diff-auto-refine-mode and ensure that refining only happens
when calling these commands interactively.
(diff--font-lock-refined): Adapt to rename of
diff-font-lock-refine.
* lisp/vc/smerge-mode.el (smerge-next, smerge-prev): Check
that 'diff-refine' is set instead of checking
'diff-auto-refine-mode' when deciding whether to refine a
conflict.

1 files changed, 9 insertions, 2 deletions

diff --git a/etc/NEWS b/etc/NEWS
index b2651855678..fc4e2c57268 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -479,8 +479,15 @@ and compares their entire trees.
 to hg revert.
 
 ** Diff mode
-*** Hunks are now automatically refined by default.
-To disable it, set the new defcustom 'diff-font-lock-refine' to nil.
++++
+*** Hunks are now automatically refined by font-lock.
+To disable refinement, set the new defcustom 'diff-refine' to nil.
+To get back the old behavior where hunks are refined as you navigate
+through a diff, set 'diff-refine' to the symbol 'navigate'.
++++
+*** 'diff-auto-refine-mode' is deprecated in favor of 'diff-refine'.
+It is no longer enabled by default and binding it no longer has any
+effect.
 
 +++
 *** Better syntax highlighting of Diff hunks.