mergetool: support --tool-help option like difftool does

diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index 1ae3c899ef4bb6d37bc5cbcb25ed927011378d90..84e34b1abaf23ef87fcccd21b0500fd21c5a1912 100644 (file)
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt
@@ -622,6 +622,7 @@ These options are mostly targeted for packing of git repositories.
 --no-walk::
 
        Only show the given revs, but do not traverse their ancestors.
+       This has no effect if a range is specified.
 
 --do-walk::