PR/47178 from Bug Hunting

PR/47178 from Bug Hunting

src/games/wtf/wtf:
- Correct `usage' (to match new `SYNOPSIS' from man page);
- augment comment on quering pkgsrc's help facility;
- correct interpretation of pkgsrc' help facility query result.

src/games/wtf/wtf.6:
- enhance `SYNOPSIS', document description (`.Dd'), and overal
  program description;
- augment description about quering pkgsrc's help facility;
- improve wording;
- augment `HISTORY' section;
- bump date.