cvsimport: Improve formating consistency

Use ' ' syntax for all commandline options mentioned in text.

Signed-off-by: Frank Lichtenheld <frank@lichtenheld.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>

Documentation/git-cvsimport.txt

@@ -65,7 +65,7 @@ the old cvs2git tool.
 	not create them if they do not exist.
 
 -k::
-	Kill keywords: will extract files with -kk from the CVS archive
+	Kill keywords: will extract files with '-kk' from the CVS archive
 	to avoid noisy changesets. Highly recommended, but off by default
 	to preserve compatibility with early imported trees. 
 
@@ -96,7 +96,7 @@ If you need to pass multiple options, separate them with a comma.
 
 -M <regex>::
 	Attempt to detect merges based on the commit message with a custom
-	regex. It can be used with -m to also see the default regexes. 
+	regex. It can be used with '-m' to also see the default regexes.
 	You must escape forward slashes. 
 
 -S <regex>::
@@ -126,7 +126,7 @@ their GIT_AUTHOR_NAME and GIT_AUTHOR_EMAIL set properly
 all along.
 +
 For convenience, this data is saved to `$GIT_DIR/cvs-authors`
-each time the -A option is provided and read from that same
+each time the '-A' option is provided and read from that same
 file each time git-cvsimport is run.
 +
 It is not recommended to use this feature if you intend to