Docs: Part 2 of the rocSOLVER documentation refresh

[amd-jnovotny]

This PR continues the rocSOLVER docs refresh with copy edit and formatting corrections for the how-to and non-autogenerated sections of the API reference docs. It also removes a now-unused file.

[tfalders]

There also seems to be a conflict that needs to be resolved

[amd-jnovotny]

@tfalders Thanks again for the feedback. I've added your suggestions to the new commit and fixed up the merge conflict at the same time. It looks like a very old (but very minor) PR got merged recently, but it was easy to resolve the conflict.