Fix a tab that somehow became 8 spaces.

Remove parentheses in a return statement to be consistent with the
rest of the file.

Rename sin_pi() in the float version to sin_pif().

Remove large comment that precedes sin_pif().  The comment
duplicates a comment in e_lgamma_r.c where the algorithm
is documented.

Requested by:	bde
Add references to vt(4) to further man-pages.

MFC after:	3 days
Final patches to the tools used to convert syscons keymaps for use with
vt.

MFC after:	3 days