emacs-27 b410f90 3/4: Document 'message-send-mail-function' in the Emacs manual

[Eli Zaretskii]

branch: emacs-27
commit b410f902d54fe50efdaf15f79f18cbd46a1d9dd0
Author: Allen Li <address@hidden>
Commit: Eli Zaretskii <address@hidden>

    Document 'message-send-mail-function' in the Emacs manual
    
    Most of the manual here addresses Message mode, yet talks about
    'send-mail-function' which is used for Mail mode.
    Fixing this completely requires more involved work, but for now at
    least document the difference here.
    
    * doc/emacs/sending.texi (Mail Sending): Mention
    'message-send-mail-function'.  (Bug#39639)
---
 doc/emacs/sending.texi | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/doc/emacs/sending.texi b/doc/emacs/sending.texi
index 246d605..8d3f961 100644
--- a/doc/emacs/sending.texi
+++ b/doc/emacs/sending.texi
@@ -361,9 +361,12 @@ twice).
 @cindex Feedmail
 @cindex Sendmail
 @cindex Mailclient
+@vindex message-send-mail-function
 @vindex send-mail-function
-  The variable @code{send-mail-function} controls how the message is
-delivered.  Its value should be one of the following functions:
+  The variable @code{message-send-mail-function} controls how the
+message is delivered (@code{send-mail-function} is used for Mail mode).
+The value of @code{send-mail-function} should be one of the following
+functions:
 
 @table @code
 @item sendmail-query-once