Fix minor formatting issue in man page for git-mergetool

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

Documentation/git-mergetool.txt

@@ -26,11 +26,11 @@ OPTIONS
 	Use the merge resolution program specified by <tool>.
 	Valid merge tools are:
 	kdiff3, tkdiff, meld, xxdiff, emerge, and vimdiff.
-
-	If a merge resolution program is not specified, 'git mergetool'
-	will use the configuration variable merge.tool.  If the
-	configuration variable merge.tool is not set, 'git mergetool'
-	will pick a suitable default.
++
+If a merge resolution program is not specified, 'git mergetool'
+will use the configuration variable merge.tool.  If the
+configuration variable merge.tool is not set, 'git mergetool'
+will pick a suitable default.
 
 Author
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