Changes

Remove \textbf from two cases where no special formatting fits

I considered \emph, but didn't find it appropriate.

Fix some formatting of examples and nonnormative content in tables

Use \firstuse instead of \textbf when introducing base clock partition types

Remove \textbf on 'active' where it is neither introduced nor deserving emphasis

This instance of 'active' doesn't seem to differ in any significant way from the other nearby uses of 'active' that have no special formatting.

Use \tablehead instead of \textbf for some kind of table title

Replace \textbf by \firstuse when terms are introduced in tables

Use item list instead of beginning each semiLinear rule with \textbf{Rule X}

Introduce \numbereddefinition instead of \textbf for numbered definitions

Use item list instead of \textbf for the only 'Proposition' there is

Remove \textbf on the single restriction that has it in a list of five

Remove exaggerated emphasis with \textbf in equation/variable balance examples

As it's clear from the context that these examples are all about these concepts anyway, it didn't seem motivated to make these terms stand out more with something like \emph.