Refactor abbrev modules in TR

Removed redundant whitespace and lines. Reworded/reformatted
comments for consistency.
Renumber section comments.

Most were off by one due to documentation changes. Also
reformat for consistency.
Clean up Typed Racket's main base type environment

Sort by manual section, reformat for consistent formatting,
remove redundant lines.
Delete trailing whitespace
Remove unnecessary `require`s

These imports are unnecessary because of the
`except-in` import of `racket` near the top.
Add a TR test that I forgot to commit

Relevant to commit 18d4eb51351bb265f69f16b82593