Paragraph tag to help text (a few more)

I ran into a few more inconsistencies. This patch was broken off from this issue:
http://drupal.org/node/100984

drupal.module
-Moved <p> *inside* t() above <ul> for consistency.

filter.module
-Moved <p> tag out of t().
--originally on line 42

node.module
-Missing closing </p> tag.
--originally on line 35
-Added <p> tag.
--originally on line 39
-Added <p> tag.
--line containing "filter_xss_admin($type->help)"
--This is output from the user changeable submission guidelines. Not likely to have <p> on its' own.

search.module
-Moved <p> tag out of t().
--originally on line 104