docs/git-clone: clarify use of --no-hardlinks option

Current text claims optimization, implying the use of
hardlinks, when this option ratchets down the level of
efficiency. This change explains the difference made by
using this option, namely copying instead of hardlinking,
and why it may be useful.

Signed-off-by: Albert L. Lash, IV <alash3@bloomberg.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-clone.txt

@@ -55,15 +55,12 @@ repository is specified as a URL, then this flag is ignored (and we
 never use the local optimizations).  Specifying `--no-local` will
 override the default when `/path/to/repo` is given, using the regular
 Git transport instead.
-+
-To force copying instead of hardlinking (which may be desirable if you
-are trying to make a back-up of your repository), but still avoid the
-usual "Git aware" transport mechanism, `--no-hardlinks` can be used.
 
 --no-hardlinks::
-	Optimize the cloning process from a repository on a
-	local filesystem by copying files under `.git/objects`
-	directory.
+	Force the cloning process from a repository on a local
+	filesystem to copy the files under the `.git/objects`
+	directory instead of using hardlinks. This may be desirable
+	if you are trying to make a back-up of your repository.
 
 --shared::
 -s::