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

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

third_party/git/t/t4013/diff.format-patch_--stdout_initial..side

@@ -0,0 +1,47 @@
+$ git format-patch --stdout initial..side
+From c7a2ab9e8eac7b117442a607d5a9b3950ae34d5a Mon Sep 17 00:00:00 2001
+From: A U Thor <author@example.com>
+Date: Mon, 26 Jun 2006 00:03:00 +0000
+Subject: [PATCH] Side
+
+---
+ dir/sub | 2 ++
+ file0   | 3 +++
+ file3   | 4 ++++
+ 3 files changed, 9 insertions(+)
+ create mode 100644 file3
+
+diff --git a/dir/sub b/dir/sub
+index 35d242b..7289e35 100644
+--- a/dir/sub
++++ b/dir/sub
+@@ -1,2 +1,4 @@
+ A
+ B
++1
++2
+diff --git a/file0 b/file0
+index 01e79c3..f4615da 100644
+--- a/file0
++++ b/file0
+@@ -1,3 +1,6 @@
+ 1
+ 2
+ 3
++A
++B
++C
+diff --git a/file3 b/file3
+new file mode 100644
+index 0000000..7289e35
+--- /dev/null
++++ b/file3
+@@ -0,0 +1,4 @@
++A
++B
++1
++2
+-- 
+g-i-t--v-e-r-s-i-o-n
+
+$