vim: plugins: Fix the style of documents

- Add missing "Requirements" for the documents of some plugins.
- Change the links for Vim scripts - use vimscript#{id} notation.
- Unify the notation for list items in "Requirements" - use "-", not "*".

doc/textobj-lastpat.txt

@@ -45,8 +45,7 @@ INTRODUCTION					*textobj-lastpat-introduction*
 
 Requirements:
 - Vim 7.2 or later
-- |textobj-user| 0.3.5 or later
-  <http://www.vim.org/scripts/script.php?script_id=2100>
+- |textobj-user| 0.3.5 or later (vimscript#2100)