Notable changes:
* First query global preferences to detect if global language setting
is in use. If there is no global language setting, or if GlobalPreferences
extension is not installed, it will fall back to changing the language
as usual. If global language setting is found, it will add an override
instead.
* If a local override is added, the undo tooltip is different and links to
the global preferences page. The task design shows mw.notify style popup
located on a bottom right corner (LTR). I deviate from the design and
re-use the old undo tooltip with a different message instead, for
consistency. The message is chosen depending on whether local storage
value `uls-gp` is set to '1' (set in mw.uls.changeLanguage).
* I removed one use of deprecated mediawiki.api.options module. One other
use still remains.
* I changed tooltip text generation from html acrobatics to use
mw.message.parseDom. Because of that I also had to move the click handler
to avoid buildup of click handlers.
* In message documentation fixed acronym -> autonym.
Bug: T198206
Change-Id: Ie2ed792e222be919522bd1cdea98042515a0619d
fa9cea4627