minirst: remove "admonition" from _admonitions...
minirst: remove "admonition" from _admonitions
The "admonition" rst primitive is split into "specific" admonitions
("attention," "caution," etc) and the "generic" admonition
("admonition"). For more, see
http://docutils.sourceforge.net/docs/ref/rst/directives.html#admonitions
The _admonitions set and keys of the _admonitiontitles dict
overlap exactly except _admonitions has an "admonition" entry.
Nowhere in Mercurial is the "admonition" admonition directive used.
Even if it were, it doesn't have a title, so it wouldn't be rendered
correctly.
So, let's remove "admonition" from the set of recognized admonition
directives.