Fix parameter : type merger with CSS change

@lesteve in going through the diff for dask-jobqueue I noticed that you wrote this comment:

```diff
+# Temporary work-around for spacing problem between parameter and parameter
+# type in the doc, see https://github.com/numpy/numpydoc/issues/215. The bug
+# has been fixed in sphinx (https://github.com/sphinx-doc/sphinx/pull/5976) but
+# through a change in sphinx basic.css except rtd_theme does not use basic.css.
+# In an ideal world, this would get fixed in this PR:
+# https://github.com/readthedocs/sphinx_rtd_theme/pull/747/files
+def setup(app):
+ app.add_stylesheet("basic.css")
```

I wonder if we might upstream some changes to the dask-sphinx-theme to resolve it more generally across dask projects.

However, I also noticed that the sytling on API docs is now oddly centered (see https://jobqueue.dask.org/en/latest/generated/dask_jobqueue.OARCluster.html#dask_jobqueue.OARCluster) , so this might not be as easy as expected.

Start from the setup(app) entry point and the basic.css workaround described in the issue. Compare the rendered API documentation at the linked OARCluster page with the theme styling, while checking the referenced Sphinx and readthedocs-sphinx-theme changes. Done means the parameter/type spacing is corrected across Dask projects without causing API documentation to become oddly centered.

Written by the indexing model from the issue text.