add normalizer that leaved conjugation

[eiennohito]

Also, typo: inflectoin_table.json -> inflection_table.json

[t-yamamura]

It would be helpful to have some more comments and documents on NormalizerLeavedConjugation. In particular, since NormalizerLeavedConjugation is a WORD_FORM_TYPE that does not exist in SudachiPy, so it helps understanding to explain how it differs from the usual normalization process.