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

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

third_party/git/Documentation/RelNotes/1.7.0.3.txt

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+Git v1.7.0.3 Release Notes
+==========================
+
+Fixes since v1.7.0.2
+--------------------
+
+ * Object files are created in a more ACL friendly way in repositories
+   where group permission is ACL controlled.
+
+ * "git add -i" didn't handle a deleted path very well.
+
+ * "git blame" padded line numbers with one extra SP when the total number
+   of lines was one less than multiple of ten due to an off-by-one error.
+
+ * "git fetch --all/--multi" used to discard information for remotes that
+   are fetched earlier.
+
+ * "git log --author=me --grep=it" tried to find commits that have "it"
+   or are written by "me", instead of the ones that have "it" _and_ are
+   written by "me".
+
+ * "git log -g branch" misbehaved when there was no entries in the reflog
+   for the named branch.
+
+ * "git mailinfo" (hence "git am") incorrectly removed initial indent from
+   paragraphs.
+
+ * "git prune" and "git reflog" (hence "git gc" as well) didn't honor
+   an instruction never to expire by setting gc.reflogexpire to never.
+
+ * "git push" misbehaved when branch.<name>.merge was configured without
+   matching branch.<name>.remote.
+
+And other minor fixes and documentation updates.