random-dfa: Don't parenthesize X^A in functor expression

Due to the way the functor expression is parsed, this led to two nested
polynomial functors when functor rewriting is disabled. Without the parens we
get just one polynomial functor.

src/random-dfa/CoalgOutput.hs

@@ -16,7 +16,7 @@ coalgB dfa = functorB dfa <> "\n\n" <> transitionsB dfa
 
 
 functorB :: DFA -> Build.Builder
-functorB dfa = "{True,False}x(X^" <> Build.decimal (dfa ^. letters) <> ")"
+functorB dfa = "{True,False}xX^" <> Build.decimal (dfa ^. letters)
 
 
 transitionsB :: DFA -> Build.Builder