Rebase-If-Necessary: Drop note about commit messages footers being added

The footers are only added with Rebase-Always, but not with
Rebase-If-Necessary.

Release-Notes: skip
Signed-off-by: Edwin Kempin <ekempin@google.com>
Change-Id: Ia56726eb9b31885dda715cb79800f94557e7b280
diff --git a/Documentation/config-project-config.txt b/Documentation/config-project-config.txt
index 31008f6..7b1baba 100644
--- a/Documentation/config-project-config.txt
+++ b/Documentation/config-project-config.txt
@@ -457,11 +457,6 @@
 NOTE: Rebasing merge commits is not supported. If a change with a merge commit
 is submitted the link:#merge_if_necessary[merge if necessary] submit action is
 applied.
-+
-When rebasing the patchset, Gerrit automatically appends onto the end of the
-commit message a short summary of the change's approvals, and a URL link back
-to the change in the web UI (see link:#submit-footers[below]). If a fast-forward
-is done no footers are added.
 
 [[rebase_always]]
 * 'rebase always':