Fix unintentional blue font color on buttons
Currently all gray (non-primary) buttons do have blue text. I always
found this somehow confusing, but could not tell why. Now I can: I
compared our special page to the regular wikitext editor, and the
buttons have black text there.
I think having the flag "progressive" on all these buttons was nothing
but a copy-paste mistake.
This patch also changes the gray background to be identical to the same
background in the regular wikitext editor.
Bug: T198796
Change-Id: I6d19fbd19fa312fa83aee72b66ca28e7d8f4516e