Documentation: fix statement about rebase.instructionFormat

Since commit 62db5247 (rebase -i: generate the script via
rebase--helper, 2017-07-14), the short hash is given in
rebase-todo. Specifying rebase.instructionFormat does not alter this
behavior, contrary to what the documentation implies.

Signed-off-by: Maarten van der Schrieck <maarten@thingsconnected.nl>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/config/rebase.txt b/Documentation/config/rebase.txt
index f19bd0e..2f48bef 100644
--- a/Documentation/config/rebase.txt
+++ b/Documentation/config/rebase.txt
@@ -38,7 +38,7 @@
 rebase.instructionFormat::
 	A format string, as specified in linkgit:git-log[1], to be used for the
 	todo list during an interactive rebase.  The format will
-	automatically have the long commit hash prepended to the format.
+	automatically have the commit hash prepended to the format.
 
 rebase.abbreviateCommands::
 	If set to true, `git rebase` will use abbreviated command names in the
diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index 9a295bc..01b2ab5 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -523,7 +523,7 @@
 +
 The commit list format can be changed by setting the configuration option
 rebase.instructionFormat.  A customized instruction format will automatically
-have the long commit hash prepended to the format.
+have the commit hash prepended to the format.
 +
 See also INCOMPATIBLE OPTIONS below.