patch applied (ghc): Avoid duplicate error report when renaming HsDoc stuff

Fri Dec 29 06:15:57 PST 2006  [email protected]
  * Avoid duplicate error report when renaming HsDoc stuff
  
  This patch is a bit of a hack to avoid a duplicate error when checking
  	class C a where
  	  op :: a -> a
  	  op2 x = x
  (This is tcfail077)
  
  For reasons I don't understand, the decl of op2 generates an HsDeclEntity,
  and that gives a renamer error which duplicates the (better) one that 
  comes from rnMethodBinds.
  
  A better fix might be to get rid of HsDeclEntities altogether.
  
  

    M ./compiler/rename/RnSource.lhs -57 +65