DOC: fix erroneous numpydoc_edit_link formatting

[sappelhoff]

This is mainly a fix for a missing linebreak in the documentation about numpydoc_edit_link which leads to a wrong rendering:

see: https://numpydoc.readthedocs.io/en/latest/install.html#sphinx-config-options

I couldn't find which version numpydoc_edit_link was deprecated, so if someone knows, it'd be good to add the version after the directive.

Then I also corrected an indent for consistency, this should have no impact on the actual rendering

[sappelhoff]

Tests are failing because the argument to the .. deprecated:: directive seems to be REQUIRED. Prior to this PR, the first word of the next sentence was parsed as the argument to the directive (erroneously).

git log -S numpydoc_edit_link did not help me to figure out in which version this was deprecated 🤔 I'll try to find it via git blame

EDIT: I was unsuccessful in finding a commit or similar of when the deprecation took place. But given that #122 occurred on 2017-10-23, I looked at the release history and it's very likely that the deprecation happend in 0.7.0 (from 2017-06-20) or earlier, so I put 0.7.0 for now.

[larsoner]

Straightforward improvement, thanks @sappelhoff !