For consistency with how normal OOjs UI widgets behave.
Only one usage outside of HTMLForm needed updating. There
are no usages in extensions in Gerrit.
Change-Id: I9b5de86307a13ca7355b7541e8683e4d6a10431f
Recreated the form with OOUI widgets. This required putting together
ComplexTitleInputWidget to handle the split namespace+title field on
this page.
Bug: T86865
Change-Id: Ice69df851137e3454ae2c9f4c75494b18cf8a75a