BUG: DOC: Fix documentation build.

The documentation was not building. The apparent cause was a problem in
parsing some `...` constructs in 1.9.0-notes.rst. Some of those
constructs looked intended as links and others just looked wrong. All
uses of `...` were replaced by inline literals ``...`` just to be safe.
I have no idea where or what the actual bug was.

Also spellchecked and reformatted for line length.

Closes #4346.
Merge pull request #4423 from charris/fix-documentation-build

BUG: DOC: Fix documentation build.