since I've run ./duplicate_oids (and found no problems) in the last
 couple of months.
Add and modify some DESCR() entries to describe functions.

 Don't know why these few were not already this way, and don't know if
  there is some hidden problem with this, but assume it was done
  accidentally as entries were copied from other operators.
 Regression tests are OK, but...
Move one block of declaration source to keep OIDs in increasing order.
 Did not change OID values, just moved source code.

 Lost these when some include files were reorganized.
 Regression test could not compile.