Add `muldiv_c` and `muxadd` peepopts #1507

Job	Run time
pre_docs_job	6s
pre_job	6s
Reusable build (ubuntu-latest)	15m 59s
Reusable build (macos-latest)	7m 22s
Try build docs (html)	1m 9s
Try build docs (latexpdf)	1m 7s
Run docs tests (ubuntu-latest)	26s
Run tests (ubuntu-latest)	4m 4s
Run tests (macos-latest)	3m 37s
	33m 56s

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