[PATCH] doc: fix a typo and clarify a sentence

[Mihir Mehta <mihir@cs.utexas.edu>]

I noticed that git-merge-base was unlikely to actually be a git command,
and tried it in my shell. Seeing that it doesn't work, I cleaned up two
places in the docs where it appears.

Signed-off-by: Mihir Mehta <mihir@cs.utexas.edu>
---
 Documentation/git-diff.txt                  | 5 +++--
 Documentation/howto/update-hook-example.txt | 2 +-
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/Documentation/git-diff.txt b/Documentation/git-diff.txt
index b180f1fa5..6173f569e 100644
--- a/Documentation/git-diff.txt
+++ b/Documentation/git-diff.txt
@@ -72,8 +72,9 @@ two blob objects, or changes between two files on disk.
 	This form is to view the changes on the branch containing
 	and up to the second <commit>, starting at a common ancestor
 	of both <commit>.  "git diff A\...B" is equivalent to
-	"git diff $(git-merge-base A B) B".  You can omit any one
-	of <commit>, which has the same effect as using HEAD instead.
+	"git diff $(git merge-base A B) B".  You can omit any one
+	of the two instances of <commit>, which has the same effect as
+	using HEAD in its place.
 
 Just in case if you are doing something exotic, it should be
 noted that all of the <commit> in the above description, except
diff --git a/Documentation/howto/update-hook-example.txt b/Documentation/howto/update-hook-example.txt
index a5193b1e5..89821ec74 100644
--- a/Documentation/howto/update-hook-example.txt
+++ b/Documentation/howto/update-hook-example.txt
@@ -80,7 +80,7 @@ case "$1" in
       info "The branch '$1' is new..."
     else
       # updating -- make sure it is a fast-forward
-      mb=$(git-merge-base "$2" "$3")
+      mb=$(git merge-base "$2" "$3")
       case "$mb,$2" in
         "$2,$mb") info "Update is fast-forward" ;;
 	*)	  noff=y; info "This is not a fast-forward update.";;
-- 
2.19.0