doc: am: say that --message-id adds a trailer

The option `--message-id` was added in a078f732 (git-am: add --message-id/--no-message-id, 2014-11-25) back when git-interpret- trailers(1) was relatively new. Let’s spell out that it is a trailer and link to the dedicated trailer command. Also use inline-verbatim for `Message-ID`. Also link to git-interpret-trailers(1) on `--signoff`. Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Kristoffer Haugsbakk committed Feb 9, 2026 at 18:34 UTC 3c18135bfd04d8ab1007137bcf565badc4ae2953
1 file changed +9 -7
Documentation/git-am.adoc
+9 -7
@@ -37,9 +37,10 @@ OPTIONS
37
38 -s::
39 --signoff::
40 - Add a `Signed-off-by` trailer to the commit message, using
41 - the committer identity of yourself.
42 - See the signoff option in linkgit:git-commit[1] for more information.
40 + Add a `Signed-off-by` trailer to the commit message (see
41 + linkgit:git-interpret-trailers[1]), using the committer identity
42 + of yourself. See the signoff option in linkgit:git-commit[1]
43 + for more information.
44
45 -k::
46 --keep::
@@ -83,10 +84,11 @@ OPTIONS
84
85 -m::
86 --message-id::
86 - Pass the `-m` flag to linkgit:git-mailinfo[1],
87 - so that the Message-ID header is added to the commit message.
88 - The `am.messageid` configuration variable can be used to specify
89 - the default behaviour.
87 + Pass the `-m` flag to linkgit:git-mailinfo[1], so that the
88 + `Message-ID` header is added as a trailer (see
89 + linkgit:git-interpret-trailers[1]). The `am.messageid`
90 + configuration variable can be used to specify the default
91 + behaviour.
92
93 --no-message-id::
94 Do not add the Message-ID header to the commit message.