Add `muldiv_c` and `muxadd` peepopts #1513

Job	Run time
pre_docs_job	5s
pre_job	4s
Reusable build (ubuntu-latest)	16m 1s
Try build docs (html)	1m 11s
Reusable build (macos-latest)	8m 58s
Try build docs (latexpdf)	1m 19s
Run tests (ubuntu-latest)	4m 14s
Run docs tests (ubuntu-latest)	34s
Run tests (macos-latest)	4m 26s
	36m 52s

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