Add classes to admonition blocks to distinguish between them

[choldgraf]

In executablebooks/sphinx-book-theme#98 we realized that there is no HTML that distinguishes between some admonition blocks because they're mapped on to the same bootstrap class here: https://github.com/pandas-dev/pydata-sphinx-theme/blob/master/pydata_sphinx_theme/bootstrap_html_translator.py#L16.

In those cases, perhaps we should also add another class that makes it possible to distinguish between them. Maybe by adding one extra append to the classes here: https://github.com/pandas-dev/pydata-sphinx-theme/blob/master/pydata_sphinx_theme/bootstrap_html_translator.py#L73 ?

[chrisjsewell]

Would it be possible to just also add the original class names to the start of the class list, before the bootstrap ones?
I don't believe there are any clashes in these class names with the bootstrap ones, for example in https://sphinx-panels.readthedocs.io I'm using the RTD CSS + Bootstrap CSS.

[jorisvandenbossche]

Yes, short term we can simply add the original class names I think.

Now, I am also certainly not married to the current approach of using the bootstrap "alert" for the admonitions. That was mainly a quick hack initially to easily style them with bootstrap (but we could probably also style the original adminition classes from sphinx similarly relatively easy, I suppose).

I already long wanted to improve the look of the admonitions, as well (and for example, adding such icons, is something I think we be good to have here in the base theme as well). It seems I still didn't open an issue about that, will do that now.

[jorisvandenbossche]

Opened an issue about the general admonition styling at #182