hedgehog builtins generators have horrible coverage

[effectfully]

PlutusCore.Generators.Hedgehog.AST defines

genSomeTypeIn :: AstGen (SomeTypeIn DefaultUni)
genSomeTypeIn = Gen.frequency
    [ (1, pure $ SomeTypeIn DefaultUniInteger)
    , (1, pure $ SomeTypeIn DefaultUniByteString)
    , (1, pure $ SomeTypeIn DefaultUniString)
    , (1, pure $ SomeTypeIn DefaultUniUnit)
    , (1, pure $ SomeTypeIn DefaultUniBool)
    ]

plutus-core/test/Main.hs defines

genConstantForTest :: AstGen (Some (ValueOf DefaultUni))
genConstantForTest =
  Gen.frequency
    [ (3, someValue <$> pure ())
    , (3, someValue <$> Gen.bool)
    , -- Smallish Integers
      (5, someValue <$> Gen.integral (Range.linear (-k1) k1))
    , -- Big Integers, generally not Ints
      (5, someValue <$> Gen.integral (Range.linear (-k2) k2))
    , -- eg "\SOc_\t\GS'v\DC4FP@-pN`\na\SI\r"
      (10, someValue <$> Gen.text (Range.linear 0 100) Gen.ascii)
    , -- eg "\246'X\b<\195]\171Y"
      (3, someValue <$> Gen.text (Range.linear 0 100) Gen.latin1)
    , -- eg "\243\190\180\141"
      (3, someValue <$> Gen.utf8 (Range.linear 0 100) Gen.unicode)
    , -- eg "\1108177\609033\384623"
      (3, someValue <$> Gen.text (Range.linear 0 100) Gen.unicode)
    , -- Bytestring
      (10, someValue <$> Gen.bytes (Range.linear 0 100))
    ]
  where
    k1 = 1000000 :: Integer
    k2 = m * m
    m = fromIntegral (maxBound :: Int) :: Integer

All of those should handle more built-in types.

Ideally though, we should simply replace hedgehog with QuickCheck there wherever possible since we already have high-quality generators for QuickCheck and the latter is better anyway.

[effectfully]

Was fixed by #6315.