Rename `ctx` -> `man` #12405

Job	Run time
regression (ubuntu-22.04, ocaml-variants.4.14.2+options,ocaml-option-flambda)	8m 22s
regression (macos-13, ocaml-variants.4.14.2+options,ocaml-option-flambda)	23m 16s
extraction	0s
gobview (ubuntu-22.04, ocaml-variants.4.14.2+options,ocaml-option-flambda, 14)	7m 37s
	39m 15s

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