Merge branch 'kh/doc-am-xref'

Doc update.

* kh/doc-am-xref:
  doc: am: fill out hook discussion
  doc: am: add missing config am.messageId
  doc: am: say that --message-id adds a trailer
  doc: am: normalize git(1) command links

diff --cc Documentation/git-am.adoc
index 972398d4575c8542f2e71742c6fd6f6c19cc099a,403181baa9fb4a2422a8ea579fa17c4a58e77dfc..384e0cd7f9b5d578eca234044dc32e5f895b83b8
--- 1/Documentation/git-am.adoc
--- 2/Documentation/git-am.adoc
+++ b/Documentation/git-am.adoc
@@@ -253,13 -249,16 +257,13 @@@ where the patch begins.  Excess whitesp
  line is automatically stripped.
  
  The patch is expected to be inline, directly following the
 -message.  Any line that is of the form:
 -
 -* three-dashes and end-of-line, or
 -* a line that begins with "diff -", or
 -* a line that begins with "Index: "
 +message.
 +include::format-patch-end-of-commit-message.adoc[]
  
 -is taken as the beginning of a patch, and the commit log message
 -is terminated before the first occurrence of such a line.
 +This means that the contents of the commit message can inadvertently
 +interrupt the processing (see the <<caveats,CAVEATS>> section below).
  
- When initially invoking `git am`, you give it the names of the mailboxes
+ When initially invoking linkgit:git-am[1], you give it the names of the mailboxes
  to process.  Upon seeing the first patch that does not apply, it
  aborts in the middle.  You can recover from this in one of two ways:
  
@@@ -277,17 -276,10 +281,17 @@@ names
  
  Before any patches are applied, ORIG_HEAD is set to the tip of the
  current branch.  This is useful if you have problems with multiple
- commits, like running 'git am' on the wrong branch or an error in the
- commits that is more easily fixed by changing the mailbox (e.g.
+ commits, like running linkgit:git-am[1] on the wrong branch or an error
+ in the commits that is more easily fixed by changing the mailbox (e.g.
  errors in the "From:" lines).
  
 +[[caveats]]
 +CAVEATS
 +-------
 +
 +:git-am: 1
 +include::format-patch-caveats.adoc[]
 +
  HOOKS
  -----
  This command can run `applypatch-msg`, `pre-applypatch`,