* tmac/doc-ditroff: Remove useless switch/variable -rC.
(doc-setup-header): Don't set page register `%'.
* tmac/doc-nroff: Remove variable `C'.
(doc-setup-page-layout): Set doc-header-space to .5i unconditionally.
(doc-setup-header): Don't set page register `%'.
Don't call `bp'.
* tmac/doc-common (doc-header): Call `ns'.
(doc-paragraph): Protect .sp with .br so that it survives the
implicit new-page trap.
* tmac/doc.tmac (Bp, Bl, doc-set-vertical-and-indent): Ditto.
* tmac/doc*:Replace ' with . for consistency in all mdoc-related
files if no effect.