Docs: Add -X option to git-merge's synopsis.

Also move -X's description next to -s's in merge-options.txt.

This makes it easier to learn how to specify merge strategy options.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-merge.txt

@@ -9,7 +9,8 @@ git-merge - Join two or more development histories together
 SYNOPSIS
 --------
 [verse]
-'git merge' [-n] [--stat] [--no-commit] [--squash] [-s <strategy>]...
+'git merge' [-n] [--stat] [--no-commit] [--squash]
+	[-s <strategy>] [-X <strategy-option>]
 	[--[no-]rerere-autoupdate] [-m <msg>] <commit>...
 'git merge' <msg> HEAD <commit>...
 

Documentation/merge-options.txt

@@ -62,6 +62,11 @@ option can be used to override --squash.
 	is used instead ('git merge-recursive' when merging a single
 	head, 'git merge-octopus' otherwise).
 
+-X <option>::
+--strategy-option=<option>::
+	Pass merge strategy specific option through to the merge
+	strategy.
+
 --summary::
 --no-summary::
 	Synonyms to --stat and --no-stat; these are deprecated and will be
@@ -74,8 +79,3 @@ option can be used to override --squash.
 -v::
 --verbose::
 	Be verbose.
-
--X <option>::
---strategy-option=<option>::
-	Pass merge strategy specific option through to the merge
-	strategy.