SpecialWatchlist: Page header cleanup

Format the three messages in header as one paragraph with three
sentences, instead of a paragraph and two split unordered lists with
one item each and inconsistent full stops.

Message changes: In 'wlheader-enotif' and 'wlheader-showupdated',
remove initial bullet point if present and add final full stop if
missing. First used the regexes below, then went through each language
file and manually changed the messages if applicable (e.g., Thai not
using full stops at all, Asian languages using '。', Devanagari
languages using '।' etc.)
  Find: ('wlheader-[^']+'\s*=>\s*)(['"])(?:\*\s*)?([\s\S]+?)\.?\2,\n
  Replace with: $1$2$3.$2,\n

Bug: 48615
Change-Id: I856f71f36d7f4b4baff5e968d88e4d3f7aeecce2
Merge "SpecialWatchlist: Page header cleanup"