feat: better quote inputs

[fybx]

Example Input

$ demo --sentence="this is a sentence" --another_arg "another quote"

Expected Output

c.parse_string("--sentence=\"this is a sentence\"") should produce the following dictionary:

{"sentence": "this is a sentence", "another_arg": "another quote"}

or if a class-level setting like "Crispy.keep_quotes" is set to True

{"sentence": "\"this is a sentence\"", "another_arg": "\"another quote\""}