fix: readme example

[TmLev]

Description

I think one example from README is a bit off:

export type ButtonVariantProps = VariantProps<typeof button>; // Should be `typeof buttonVariants`.
export const buttonVariants = cva("…", ...);

export const button = (props: ButtonProps) => buttonVariants(props);

Additional context

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What is the purpose of this pull request?

Fix the example.

• Bug fix
• New Feature
• Documentation update
• Other

Before submitting the PR, please make sure you do the following

• Read the Contributing Guidelines.
• Follow the Style Guide.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).

[joe-bell]

Thank you!