documentation: git-config minor cleanups

Change push.default's description to add hyphens between values and
descriptions to make the manpage easier to read.  The html version is
readable either way.

Change status.showUntrackedFiles to make item descriptions be
sentences and to use the same asciidoc format as push.default.  The
only visual change is the additions of "."

Signed-off-by: Cliff Frey <cliff@meraki.com>
Acked-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/config.txt

@@ -1550,12 +1550,12 @@ push.default::
 	no refspec is implied by any of the options given on the command
 	line. Possible values are:
 +
-* `nothing` do not push anything.
-* `matching` push all matching branches.
+* `nothing` - do not push anything.
+* `matching` - push all matching branches.
   All branches having the same name in both ends are considered to be
   matching. This is the default.
-* `tracking` push the current branch to its upstream branch.
-* `current` push the current branch to a branch of the same name.
+* `tracking` - push the current branch to its upstream branch.
+* `current` - push the current branch to a branch of the same name.
 
 rebase.stat::
 	Whether to show a diffstat of what changed upstream since the last
@@ -1755,9 +1755,9 @@ status.showUntrackedFiles::
 	the untracked files. Possible values are:
 +
 --
-	- 'no'     - Show no untracked files
-	- 'normal' - Shows untracked files and directories
-	- 'all'    - Shows also individual files in untracked directories.
+* `no` - Show no untracked files.
+* `normal` - Show untracked files and directories.
+* `all` - Show also individual files in untracked directories.
 --
 +
 If this variable is not specified, it defaults to 'normal'.