v1.22.2: Render man page headings as GenericHeadings

This makes man pages nicer to read out of the box.

Other minor changes in this release:
* Use 16M color themes when requested, used to be 8 color themes (oops)
* Print less text on bad command lines to make the error message easier
  to find
* Render non-breaking spaces, we used to treat them as non-printable