Add `muldiv_c` and `muxadd` peepopts #1505

Job	Run time
pre_docs_job	11s
pre_job	5s
Reusable build (ubuntu-latest)	4m 16s
Try build docs (html)	19s
Reusable build (macos-latest)	3m 23s
Try build docs (latexpdf)	18s
Run tests	0s
Run docs tests	0s
	8m 32s

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