A negative value if a is before b, a positive value if a is after b, or 0 if they are the same
VALID_NUM_TYPES order:
decimal
latin_letter
month_name
day_of_week
greek_letter
greek_letter_english_name
roman
chinese_words
chinese_financial
chinese_heavenly_stem
chinese_earthly_branch
chinese_solar_term
cyrillic_letter
hebrew_letter
binary
octal
hexadecimal
arabic
english_cardinal
english_words
french_words
astrological_sign
nato_phonetic
Compare two num types based on their order in the VALID_NUM_TYPES array