two times the same option in README.rst

[sblondon]

The 'skip-atexit' option is displayed two times (https://uwsgi-docs.readthedocs.io/en/latest/Options.html#skip-atexit). The difference is in the help info: the first one is about hooks, the second one is about teardown.

I have two hypothesis:

• one of the 'skip-atexit' option shoud be renamed to the corresponding option
• the help should be merged into one. The 'help' could become 'skip atexit hooks and teardown (ignored by the master)'.

I wanted to provide a patch but I don't know what the right solution is.