Specification clean-up (#1599)

Formatting fixes, no changes to the meaning of anything:

Change lines with normal text above 80 chars to fit in 80 columns (did not change math, tables, `\code{...}`). Remove certain unnecessary `{}` after LaTeX commands. Add `\noindent` to de-dent `\code{}` and math elements long enough to get their own line (when not at the beginning of a paragraph). Correct quoted phrases to use backquote/single_quote (many code snippets in comments use backquotes as in markdown, and that has not been changed). Correct indentation in some `\begin{itemize}...\end{itemize}` constructs.

Author: eernstg