doc/git-branch: fix --force description typo

Update the description of --force to use '<start-point>' rather than
'<startpoint>' to match the spelling used everywhere else in the
git-branch documentation.

Signed-off-by: Kyle Meyer <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: kyleam

Documentation/git-branch.txt

@@ -116,7 +116,7 @@ OPTIONS
 
 -f::
 --force::
-	Reset <branchname> to <startpoint>, even if <branchname> exists
+	Reset <branchname> to <start-point>, even if <branchname> exists
 	already. Without `-f`, 'git branch' refuses to change an existing branch.
 	In combination with `-d` (or `--delete`), allow deleting the
 	branch irrespective of its merged status, or whether it even