Fix linting issues

[wwarriner]

Fixed various linting issues. There is one known issue we can't resolve on the VSCode side of things. The VSCode markdown linter extension thinks that admonitions are indented code blocks, and it complains if there are both fenced (with backtick `) and indented code blocks in the same document. This can't currently be resolved.

[mdefende]

There is a way to ignore specific linting warning codes if we want to investigate that. If we don't think there are going to be actual instances of this warning in what we are creating down the line

[mdefende]

Additionally:

Individual warnings can be suppressed with comments in the Markdown file itself:

<!-- markdownlint-disable MD037 -->
deliberate space * in * emphasis
<!-- markdownlint-enable MD037 -->

[mdefende]

Seems great