Add `muldiv_c` and `muxadd` peepopts #1510

Job	Run time
pre_job	4s
pre_docs_job	4s
Try build docs (html)	1m 12s
Reusable build (ubuntu-latest)	15m 57s
Reusable build (macos-latest)	11m 48s
Try build docs (latexpdf)	1m 7s
Run docs tests (ubuntu-latest)	49s
Run tests (ubuntu-latest)	4m 43s
Run tests (macos-latest)	5m 52s
	41m 36s

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