How to remove the Alpha channel.

Hi @casesandberg,
I am using `ChromePicker` with `disableAlpha={false}` everthing is fine, but how do I remove `alpha channel`.
I mean I don't want to show it in the page.

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Start from the ChromePicker usage shown in the issue and inspect how the disableAlpha prop is documented and applied. Confirm the documented setting that hides the alpha channel, and update the relevant usage guidance if it is missing; done when the example clearly shows a picker without the alpha control.

Written by the indexing model from the issue text.