git.txt: fix list continuation

Remove a spurious empty line which prevented asciidoc from recognizing a
list continuation mark ('+'), so that it does not get output literally any
more.
Signed-off-by: NMichael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Documentation/git.txt

@@ -619,7 +619,6 @@ where:
                          contents of <old|new>,
 	<old|new>-hex:: are the 40-hexdigit SHA1 hashes,
 	<old|new>-mode:: are the octal representation of the file modes.
-
 +
 The file parameters can point at the user's working file
 (e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`