Point wikitext markup link in warning to MW.org

Bug: T69273
Change-Id: Ie9e7307909c18eabaa0e294ac7a1e9c3a3f3f4d1
Warn users who write ';' or ':' on a new line that it won't work

Bug: T71689
Change-Id: Id0ebae825ea013fe0968dcf458922802290e0b2b
Merge "Point wikitext markup link in warning to MW.org"
Merge "Warn users who write ';' or ':' on a new line that it won't work"