git-rebase.sh: update help messages a bit

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 7d8383433ce9995c1950705fb9b345eff1bd652d..ab641bf5a9984b7ab2dfea787a0db5704f79a448 100644 (file)
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -1412,6 +1412,14 @@ credential.<url>.*::
 credentialCache.ignoreSIGHUP::
        Tell git-credential-cache--daemon to ignore SIGHUP, instead of quitting.
 
+completion.commands::
+       This is only used by git-completion.bash to add or remove
+       commands from the list of completed commands. Normally only
+       porcelain commands and a few select others are completed. You
+       can add more commands, separated by space, in this
+       variable. Prefixing the command with '-' will remove it from
+       the existing list.
+
 include::diff-config.txt[]
 
 difftool.<tool>.path::