merge(third_party/git): Merge squashed git subtree at v2.23.0

Merge commit '1b593e1ea4' as 'third_party/git'

third_party/git/Documentation/git-whatchanged.txt

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+git-whatchanged(1)
+==================
+
+NAME
+----
+git-whatchanged - Show logs with difference each commit introduces
+
+
+SYNOPSIS
+--------
+[verse]
+'git whatchanged' <option>...
+
+DESCRIPTION
+-----------
+
+Shows commit logs and diff output each commit introduces.
+
+New users are encouraged to use linkgit:git-log[1] instead.  The
+`whatchanged` command is essentially the same as linkgit:git-log[1]
+but defaults to show the raw format diff output and to skip merges.
+
+The command is kept primarily for historical reasons; fingers of
+many people who learned Git long before `git log` was invented by
+reading Linux kernel mailing list are trained to type it.
+
+
+Examples
+--------
+`git whatchanged -p v2.6.12.. include/scsi drivers/scsi`::
+
+	Show as patches the commits since version 'v2.6.12' that changed
+	any file in the include/scsi or drivers/scsi subdirectories
+
+`git whatchanged --since="2 weeks ago" -- gitk`::
+
+	Show the changes during the last two weeks to the file 'gitk'.
+	The "--" is necessary to avoid confusion with the *branch* named
+	'gitk'
+
+GIT
+---
+Part of the linkgit:git[1] suite