Doc: document "A...B" form for <tree-ish> in checkout and switch

Denton-L · gitster · commit c693ef781bef · 2020-10-07T09:49:05.000-07:00
Using "A...B" has been supported for the &lt;tree-ish&gt; argument for a
while. However, its support has never been explicitly documented.

Explicitly document it so that users know that it is available.

Signed-off-by: Denton Liu &lt;liu.denton@gmail.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
@@ -350,6 +350,10 @@ leave out at most one of `A` and `B`, in which case it defaults to `HEAD`.
 <tree-ish>::
 	Tree to checkout from (when paths are given). If not specified,
 	the index will be used.
++
+As a special case, you may use `"A...B"` as a shortcut for the
+merge base of `A` and `B` if there is exactly one merge base. You can
+leave out at most one of `A` and `B`, in which case it defaults to `HEAD`.
 
 \--::
 	Do not interpret any more arguments as options.
diff --git a/Documentation/git-restore.txt b/Documentation/git-restore.txt
@@ -40,6 +40,10 @@ OPTIONS
 +
 If not specified, the contents are restored from `HEAD` if `--staged` is
 given, otherwise from the index.
++
+As a special case, you may use `"A...B"` as a shortcut for the
+merge base of `A` and `B` if there is exactly one merge base. You can
+leave out at most one of `A` and `B`, in which case it defaults to `HEAD`.
 
 -p::
 --patch::
