Fix #800
Fix #800

Adds some deduping to function application paren warnings, and also
limits the number generated when it's easy.

pranjaltale16/codeworld,pranjaltale16/codeworld,pranjaltale16/codeworld,alphalambda/codeworld,google/codeworld,alphalambda/codeworld,google/codeworld,google/codeworld,alphalambda/codeworld