Documentation/urls: Remove spurious example markers

Documentation/urls: Remove spurious example markers

In urls.txt (which is included from git-{clone,fetch,push}.txt)
several item lists are surrounded by example block markers. This is
problematic for two reasons:

- None of these lists are example lists, so they should not be marked as
  such semantically.
- The html output looks weird (bulleted list with left sidebar).

Therefore, remove the example block markers. Output by the man backend
is unaffected.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>