Documentation/git-merge.txt: fix formatting of example block

You need at least four dashes in a line to have it recognized as listing block delimiter by asciidoc.

---
 Documentation/git-merge.txt | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index 8c7f2f6..a74c371 100644
@@ -186,11 +186,11 @@ In such a case, you can "unwrap" the tag yourself before feeding it
 to `git merge`, or pass `--ff-only` when you do not have any work on
 your own. e.g.
 
----
+----
 git fetch origin
 git merge v1.2.3^0
 git merge --ff-only v1.2.3
----
+----
 
 
 HOW CONFLICTS ARE PRESENTED

1.8.4

-- 
Andreas Schwab, [email protected]
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Thanks. It seems that this was broken from the beginning at 77c72780 (Documentation: merging a tag is a special case, 2013-03-21).

Will apply.