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

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

third_party/git/Documentation/RelNotes/1.8.5.3.txt

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+Git v1.8.5.3 Release Notes
+==========================
+
+Fixes since v1.8.5.2
+--------------------
+
+ * The "--[no-]informative-errors" options to "git daemon" were parsed
+   a bit too loosely, allowing any other string after these option
+   names.
+
+ * A "gc" process running as a different user should be able to stop a
+   new "gc" process from starting.
+
+ * An earlier "clean-up" introduced an unnecessary memory leak to the
+   credential subsystem.
+
+ * "git mv A B/", when B does not exist as a directory, should error
+   out, but it didn't.
+
+ * "git rev-parse <revs> -- <paths>" did not implement the usual
+   disambiguation rules the commands in the "git log" family used in
+   the same way.
+
+ * "git cat-file --batch=", an admittedly useless command, did not
+   behave very well.
+
+Also contains typofixes, documentation updates and trivial code clean-ups.