man: some typesetting and style fixes for recent additions

[kib]

Summary

Mostly start each sentence from a new line.  Also add more pretty
typesetting to cdce(4).

[imp]

I like these. Made a couple of minor suggestions you can take or leave as you see fit.

bin/nproc/nproc.1

37

Maybe avoid contractions and use 'Do not use this option' instead?

share/man/man4/cdce.4

93

I think 'For example: ' reads better here.

[kib]

imp' suggestions