Cleanup of comments in MOM_ALE_sponge.F90

  Extensive inconsequential cleanup in MOM_ALE_sponge.F90, including the
elimination of a dozen unnecessary index-range elements of the ALE_sponge_CS and
modifying a number of comments to be much more descriptive.  This included the
correction of numerous spelling errors and other typos in comments.  All answers
are bitwise identical.