Update list.{count, index, remove} to accept object type

[randolf-scholz]

Partially fixes #15271

[github-actions]

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

optuna (https://github.com/optuna/optuna)
+ tests/visualization_tests/test_rank.py:699: error: Need type annotation for "x2"  [var-annotated]

pwndbg (https://github.com/pwndbg/pwndbg)
+ pwndbg/aglib/elf.py:448: error: Unused "type: ignore" comment  [unused-ignore]

colour (https://github.com/colour-science/colour)
- colour/utilities/network.py:1772: error: Argument 1 to "remove" of "list" has incompatible type "PortNode"; expected "Self"  [arg-type]
- colour/notation/munsell.py:2573: error: Argument 1 to "index" of "list" has incompatible type "tuple[Any, Any, Any]"; expected "tuple[float, float]"  [arg-type]
- colour/notation/munsell.py:2578: error: Argument 1 to "index" of "list" has incompatible type "tuple[Any, Any, Any]"; expected "tuple[float, float]"  [arg-type]
- colour/notation/munsell.py:2585: error: Argument 1 to "index" of "list" has incompatible type "tuple[Any, Any, Any]"; expected "tuple[float, float]"  [arg-type]
- colour/notation/munsell.py:2590: error: Argument 1 to "index" of "list" has incompatible type "tuple[Any, Any, Any]"; expected "tuple[float, float]"  [arg-type]
- colour/plotting/models.py:1457: error: Incompatible types in assignment (expression has type "Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | complex | str | _NestedSequence[complex | bytes | str]", variable has type "ndarray[tuple[Any, ...], dtype[Any]]")  [assignment]
+ colour/plotting/models.py:1457: error: Incompatible types in assignment (expression has type "Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | complex | str | _NestedSequence[complex | bytes | str]", variable has type "ndarray[Any, Any]")  [assignment]

xarray (https://github.com/pydata/xarray)
+ xarray/tests/test_concat.py: note: In function "create_typed_datasets":
+ xarray/tests/test_concat.py:112: error: Argument 1 to "reshape" has incompatible type "list[Timedelta]"; expected "_SupportsArray[dtype[Never]] | _NestedSequence[_SupportsArray[dtype[Never]]]"  [arg-type]
+ xarray/tests/test_concat.py: note: At top level:
+ xarray/tests/test_backends.py:2062: error: Need type annotation for "expected"  [var-annotated]

dedupe (https://github.com/dedupeio/dedupe)
+ dedupe/labeler.py:410: error: List item 1 has incompatible type "Iterable[Literal[0, 1]]"; expected "_SupportsArray[dtype[signedinteger[_64Bit]]] | _NestedSequence[_SupportsArray[dtype[signedinteger[_64Bit]]]]"  [list-item]

pandas (https://github.com/pandas-dev/pandas)
+ pandas/core/dtypes/dtypes.py:974: error: Need type annotation for "np_dtype"  [var-annotated]
+ pandas/core/dtypes/dtypes.py:975: error: Argument 1 has incompatible type "list[dtype[Any] | ExtensionDtype]"; expected "_SupportsArray[dtype[Never]] | _NestedSequence[_SupportsArray[dtype[Never]]]"  [arg-type]
+ pandas/core/arrays/sparse/array.py:1452: error: Need type annotation for "sparse_values"  [var-annotated]
+ pandas/plotting/_matplotlib/misc.py:170: error: Need type annotation for "s"  [var-annotated]
+ pandas/plotting/_matplotlib/core.py:1205: error: List item 0 has incompatible type "Number | number[Any, int | float | complex]"; expected "_SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]]"  [list-item]

scipy-stubs (https://github.com/scipy/scipy-stubs)
+ tests/special/test_ufuncs.pyi:69: error: Argument 1 to "__call__" of "_UFunc11f" has incompatible type "list[complex]"; expected "CanArrayND[floating[_16Bit] | integer[Any] | numpy.bool[builtins.bool], tuple[Any, ...]] | SequenceND[CanArrayND[floating[_16Bit] | integer[Any] | numpy.bool[builtins.bool], tuple[Any, ...]]] | SequenceND[JustFloat | int]"  [arg-type]
+ tests/special/test_ufuncs.pyi:69: note: "list" is missing following "CanArrayND" protocol member:
+ tests/special/test_ufuncs.pyi:69: note:     __array__

jax (https://github.com/google/jax)
+ jax/experimental/key_reuse/_core.py:395: error: Unused "type: ignore" comment  [unused-ignore]

[randolf-scholz]

Hm, not exactly sure what's going on with numpy, my best guess is that since _NestedSequence is defined with (https://github.com/numpy/numpy/blob/main/numpy/_typing/_nested_sequence.py)

    def count(self, value: Any, /) -> int:
        """Return the number of occurrences of `value`."""
        raise NotImplementedError

    def index(self, value: Any, /) -> int:
        """Return the first index of `value`."""
        raise NotImplementedError

then after we make list use object rather than Any, this is still a subtype but possibly no longer a "proper_subtype". This is a mypy interal distinction and likely needs to be addressed on mypys side.