add type hints to components

[michaelbynum]

Changes proposed in this PR:

• Add some type hints to components

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1. I agree my contributions are submitted under the BSD license.
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[jsiirola]

It looks like there might be a workaround to avoid the function call:

    @overload
    def __getitem__(self, index) -> _BlockData:
        ...

    __getitem__ = IndexedComponent.__getitem__  # type: ignore

[michaelbynum]

It looks like there might be a workaround to avoid the function call:

    @overload
    def __getitem__(self, index) -> _BlockData:
        ...

    __getitem__ = IndexedComponent.__getitem__  # type: ignore

Genius!!!