Replace deprecated calls to OutputPage::parseInline()

Replace deprecated calls to OutputPage::parseInline()

Every one of these seemed to previously use the wrong value for
`$interface` -- the interface messages in ProtectionForm and
SpecialVersion were being parsed as content language (which is the
default for `OutputPage::parseInline`), and the one place where we
have actual data in the content language (the user signature, which
gets parsed in the content language with the rest of the (talk) page
content, see Parser.php::pstPass2) was being parsed as an interface
message!

Forcing the caller to be very explicit about AsContent() or AsInterface()
will help mitigate this in the future, one hopes.

Bug: T198214
Change-Id: Ib9d5d8d733a47c967bdf7db3e23fa39f11687063