Rollup merge of #24727 - rkruppe:reference-audit, r=steveklabnik

It was in pretty good shape, but since that is my pet peeve, I clarified the compiler/interpreter distinction and why it is irrelevant for this section. Otherwise only a couple of minor clarifications, and weasel words where reality is more complicated than the text accounted for (e.g., there is more than one kind of library).

r? @steveklabnik

diff --cc src/doc/reference.md
Simple merge