Add `muldiv_c` and `muxadd` peepopts #1504

Job	Run time
pre_job	5s
pre_docs_job	5s
Reusable build (ubuntu-latest)	4m 7s
Try build docs (html)	21s
Reusable build (macos-latest)	2m 52s
Try build docs (latexpdf)	23s
Run docs tests	0s
Run tests	0s
	7m 53s

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