[fitsbits] Proposed Changes to the FITS Standard

* p92: the discussion at the bottom should indicate that the diurnal
Doppler correction is only weakly dependent on position and therefore
great accuracy is not required.

Depends on the context, and on what's meant by "no great accuracy": it's
1 m/s for 7 arcsec (worst case position on the sky), so for planet
searches we need arcsecond precision or so (our best precision is under
1 m/s, and we want some safety margin to keep that particular contribution
to the error budget negligible). Perhaps just give the 7" -- 1 m/s
equivalence here and let readers make their own decision?