emacs-29 64fe6bdb61: Improve 'describe-char-fold-equivalences' docstring

[Robert Pluim]

branch: emacs-29
commit 64fe6bdb618ff37336b3a8c635f23fc807785ef2
Author: Robert Pluim <rpluim@gmail.com>
Commit: Robert Pluim <rpluim@gmail.com>

    Improve 'describe-char-fold-equivalences' docstring
    
    * lisp/char-fold.el (describe-char-fold-equivalences): Explain what
    the output looks like.
---
 lisp/char-fold.el | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/lisp/char-fold.el b/lisp/char-fold.el
index eff2f5558b..6da2dae847 100644
--- a/lisp/char-fold.el
+++ b/lisp/char-fold.el
@@ -436,7 +436,23 @@ specify the character).  With no input, i.e. when CHAR is 
nil,
 describe all available character equivalences of `char-fold-to-regexp'.
 Optional argument LAX (interactively, the prefix argument), if
 non-nil, means also include partially matching ligatures and
-non-canonical equivalences."
+non-canonical equivalences.
+
+Each line of the display shows the equivalences in two different
+ways separated by a colon:
+
+    - as the literal character or sequence
+    - using an ASCII-only escape syntax
+
+For example, for the letter \\='r\\=', the first line is
+
+    r: ?\\N{LATIN SMALL LETTER R}
+
+which is for the requested character itself, and a later line has
+
+    ṟ: ?\\N{LATIN SMALL LETTER R}?\\N{COMBINING MACRON BELOW}
+
+which clearly shows what the constituent characters are."
   (interactive (list (ignore-errors
                        (read-char-by-name
                         (format-prompt "Unicode name, single char, or hex"