This deprecates a number of methods which returned arrays by reference and
exposed internal representation details of the ParserOutput. It also
regularizes the return values to return consistent LinkTarget values,
working around the wide variety of different internal storage formats
used for links.
In the future, once these methods which expose the internal representation
are removed, we can simplify our internal storage as well. But for the
moment we add the new getter without changing the internal representation.
Note that by returning TitleValue objects this new interface also provides
a means to fix the issue identified in T204792 where interwiki and namespace
prefixes were getting confused. A TitleValue properly distinguishes between
these -- although the callers will still have to be careful to use it as
a TitleValue and not attempt to reparse it.
These methods also correctly handle fragments, which are present for the
language link type but stripped for the other linkt types.
Bug: T204792
Change-Id: I48a2077b9645124f83082afd953d6bf7a861270b
