Docs: Drop inline callouts

[nik9000]

We've not going to support inline callouts in asciidoctor. We're going to need to drop all of them from all branches of our docs before we can build them with asciidoctor. We use them fairly frequently in the SQL docs but they are rare otherwise.

[nik9000]

Inline callouts look like this:

----
POST <1> /_search/scroll <2>
----
<1> words
<2> other words

In asciidoctor all callouts have to be at the end of the line.

[nik9000]

Right now we don't have an enforcement mechanism to make sure that we can build the docs with asciidoctor. It wouldn't pass anyway because of a couple of this and one other strange failure in the reference docs. We also can't current run asciidoctor in CI, but I'm working on that too.