json: improve bytes handling

[sobolevn]

dumps and detect_encoding support bytearray:

>>> import json

>>> json.loads(bytearray(b'false'))
False

>>> json.detect_encoding(bytearray(b''))
'utf-8'

But, not memoryview:

>>> json.loads(memoryview(b'false'))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/sobolev/.pyenv/versions/3.10.0/lib/python3.10/json/__init__.py", line 339, in loads
    raise TypeError(f'the JSON object must be str, bytes or bytearray, '
TypeError: the JSON object must be str, bytes or bytearray, not memoryview

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

optuna (https://github.com/optuna/optuna)
- optuna/storages/_rdb/storage.py:388: error: Argument 1 to "loads" has incompatible type "Column"; expected "Union[str, bytes]"
+ optuna/storages/_rdb/storage.py:388: error: Argument 1 to "loads" has incompatible type "Column"; expected "Union[str, bytes, bytearray]"
- optuna/storages/_rdb/storage.py:398: error: Argument 1 to "loads" has incompatible type "Column"; expected "Union[str, bytes]"
+ optuna/storages/_rdb/storage.py:398: error: Argument 1 to "loads" has incompatible type "Column"; expected "Union[str, bytes, bytearray]"
- optuna/storages/_rdb/storage.py:409: error: Argument 1 to "loads" has incompatible type "Column"; expected "Union[str, bytes]"
+ optuna/storages/_rdb/storage.py:409: error: Argument 1 to "loads" has incompatible type "Column"; expected "Union[str, bytes, bytearray]"
- optuna/storages/_rdb/storage.py:420: error: Argument 1 to "loads" has incompatible type "Column"; expected "Union[str, bytes]"
+ optuna/storages/_rdb/storage.py:420: error: Argument 1 to "loads" has incompatible type "Column"; expected "Union[str, bytes, bytearray]"
- optuna/storages/_rdb/storage.py:454: error: Argument 1 to "loads" has incompatible type "Column"; expected "Union[str, bytes]"
+ optuna/storages/_rdb/storage.py:454: error: Argument 1 to "loads" has incompatible type "Column"; expected "Union[str, bytes, bytearray]"
- optuna/storages/_rdb/storage.py:455: error: Argument 1 to "loads" has incompatible type "Column"; expected "Union[str, bytes]"
+ optuna/storages/_rdb/storage.py:455: error: Argument 1 to "loads" has incompatible type "Column"; expected "Union[str, bytes, bytearray]"

[hauntsaninja]

Lgtm

[JelleZijlstra]

loads explicitly checks for str | bytes | bytearray. detect_encoding does .startswith which doesn't exist on any other well-known buffer type.