Add `muldiv_c` and `muxadd` peepopts #1534

Job	Run time
pre_job	4s
pre_docs_job	4s
Reusable build (ubuntu-latest)	15m 51s
Try build docs (html)	1m 1s
Reusable build (macos-latest)	8m 31s
Try build docs (latexpdf)	1m 15s
Run docs tests (ubuntu-latest)	29s
Run tests (ubuntu-latest)	6m 39s
Run tests (macos-latest)	6m 42s
	40m 36s

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