[unstable option] `skip_macro_invocations`

[tommilligan]

Tracking issue for unstable option: skip_macro_invocations.

• Option documentation.

From discussion here: #5324 (comment)

See Processes.md, "Stabilising an Option":

• Is the default value correct?
• The design and implementation of the option are sound and clean.
• The option is well tested, both in unit tests and, optimally, in real usage.
• There is no open bug about the option that prevents its use.