Improve documentation of 'diff-font-lock-prettify'

* lisp/vc/diff-mode.el (diff-font-lock-prettify): Doc fix.

* etc/NEWS: Minor copyedits.

2 files changed, 11 insertions, 1 deletions

diff --git a/etc/NEWS b/etc/NEWS
index e8618152ed9..b9e9e28db4b 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -734,6 +734,10 @@ With a prefix argument asks for a command, so for example,
 'C-u M-x vc-log-search RET git log -1 f302475 RET' will display
 just one log entry found by its revision number.
 
+*** 'C-x v =' can now mimic Magit's diff format.
+Set the new user option 'diff-font-lock-prettify' to t for that, see
+below under "Diff mode".
+
 ** Diff mode
 +++
 *** Hunks are now automatically refined by font-lock.
@@ -754,6 +758,8 @@ according to the appropriate major mode.  Customize the new option
 
 *** File headers can be shortened, mimicking Magit's diff format.
 To enable it, set the new user option 'diff-font-lock-prettify' to t.
+On GUI frames, this option also displays the insertion and deletion
+indicators on the left fringe.
 
 +++
 *** Prefix arg of 'diff-goto-source' means jump to the old revision
diff --git a/lisp/vc/diff-mode.el b/lisp/vc/diff-mode.el
index c4812e81d40..19f9c802d40 100644
--- a/lisp/vc/diff-mode.el
+++ b/lisp/vc/diff-mode.el
@@ -109,7 +109,11 @@ You can always manually refine a hunk with `diff-refine-hunk'."
                  (const :tag "Refine hunks during navigation" navigation)))
 
 (defcustom diff-font-lock-prettify nil
-  "If non-nil, font-lock will try and make the format prettier."
+  "If non-nil, font-lock will try and make the format prettier.
+
+This mimics the Magit's diff format by making the hunk header
+less cryptic, and on GUI frames also displays insertion and
+deletion indicators on the left fringe (if it's available)."
   :version "27.1"
   :type 'boolean)