Improve_Color type alias of PIL.Image (#8210)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>

Author: 3 people

stubs/Pillow/PIL/Image.pyi

@@ -22,7 +22,10 @@ _Box: TypeAlias = tuple[int, int, int, int]
 _ConversionMatrix: TypeAlias = Union[
     tuple[float, float, float, float], tuple[float, float, float, float, float, float, float, float, float, float, float, float],
 ]
-_Color: TypeAlias = float | tuple[float, ...]
+# `str` values are only accepted if mode="RGB" for an `Image` object
+# `float` values are only accepted for certain modes such as "F"
+# See https://pillow.readthedocs.io/en/stable/reference/Image.html#PIL.Image.new
+_Color: TypeAlias = Union[int, tuple[int], tuple[int, int, int], tuple[int, int, int, int], str, float, tuple[float]]
 
 class _Writeable(SupportsWrite[bytes], Protocol):
     def seek(self, __offset: int) -> Any: ...
@@ -220,7 +223,7 @@ class Image:
 class ImagePointHandler: ...
 class ImageTransformHandler: ...
 
-def new(mode: _Mode, size: tuple[int, int], color: float | tuple[float, ...] | str = ...) -> Image: ...
+def new(mode: _Mode, size: tuple[int, int], color: _Color = ...) -> Image: ...
 def frombytes(mode: _Mode, size: tuple[int, int], data, decoder_name: str = ..., *args) -> Image: ...
 def frombuffer(mode: _Mode, size: tuple[int, int], data, decoder_name: str = ..., *args) -> Image: ...
 def fromarray(obj, mode: _Mode | None = ...) -> Image: ...