refs.c: spell NULL pointer as NULL

diff --git a/Documentation/git-cat-file.txt b/Documentation/git-cat-file.txt
index 21cffe2bcd0d5907efda9d525228e3f78a5cff65..322f5ed3155887ef69876bd439a12c4641007c9e 100644 (file)
--- a/Documentation/git-cat-file.txt
+++ b/Documentation/git-cat-file.txt
@@ -54,7 +54,7 @@ OPTIONS
 
 --textconv::
        Show the content as transformed by a textconv filter. In this case,
-       <object> has be of the form <treeish>:<path>, or :<path> in order
+       <object> has be of the form <tree-ish>:<path>, or :<path> in order
        to apply the filter to the content recorded in the index at <path>.
 
 --batch::