Trim apologetic docstring of deprecated function

It served its purpose at the time, of helping me work through my API
designer guilt.  But now it’s just taking up space and time.

skyfield/positionlib.py

@@ -55,21 +55,7 @@ def position_of_radec(ra_hours, dec_degrees, distance_au=_GIGAPARSEC_AU,
 
 def position_from_radec(ra_hours, dec_degrees, distance=1.0, epoch=None,
                         t=None, center=None, target=None):
-    """DEPRECATED version of ``position_of_radec()``.
-
-    Problems:
-
-    * The ``distance`` parameter specifies no unit, contrary to Skyfield
-      best practices.  I have no idea what I was thinking.
-
-    * The default ``distance`` is far too small, since most objects for
-      which users specify an RA and declination are out on the celestial
-      sphere.  The hope was that users would see the length 1.0 and
-      think, “ah, yes, that’s obviously a fake placeholder value.”  But
-      it’s more likely that users will not even check the distance, or
-      maybe not even realize that a distance is involved.
-
-    """
+    """DEPRECATED version of ``position_of_radec()``."""
     return position_of_radec(ra_hours, dec_degrees, distance, epoch,
                              t, center, target)