Docs: Use "-l::\n--long\n" format in OPTIONS sections

The OPTIONS section of a documentation file contains a list
of the options a git command accepts.

Currently there are several variants to describe the case that
different options (almost) do the same in the OPTIONS section.

Some are:

 -f, --foo::
 -f|--foo::
 -f | --foo::

But AsciiDoc has the special form:

 -f::
 --foo::

This patch applies this form to the documentation of the whole git suite,
and removes useless em-dash prevention, so \--foo becomes --foo.

Signed-off-by: Stephan Beyer <s-beyer@gmx.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/git-fmt-merge-msg.txt b/Documentation/git-fmt-merge-msg.txt
index 328cc54..2a7cfb9 100644
--- a/Documentation/git-fmt-merge-msg.txt
+++ b/Documentation/git-fmt-merge-msg.txt
@@ -33,11 +33,13 @@
 	Do not list one-line descriptions from the actual commits being
 	merged.
 
---summary,--no-summary::
+--summary::
+--no-summary::
 	Synonyms to --log and --no-log; these are deprecated and will be
 	removed in the future.
 
---file <file>, -F <file>::
+-F <file>::
+--file <file>::
 	Take the list of merged objects from <file> instead of
 	stdin.