feat: Add per-function HISTORY sections

[gwhitney]

This PR implements a facility for including HISTORY sections in the block of documentation comments for each function, and retroactively adds such sections to a little over a dozen functions, including all in the types category and scattered other examples.

The idea is that going forward, any function that is touched should have its HISTORY section added or updated if it is already there. It will be beneficial to get this merged before v16, so that the PRs there, which touch many functions, will greatly expand the coverage of these HISTORY sections.

Adds a test that all functions have a HISTORY section except those on a list of known exceptions, which should be whittled down whenever HISTORY is added to a function. This facility will ensure all new functions start with a HISTORY section which should consist of one line, indicating the version number in which the function is being added.

Resolves #3341.