[Feature]: Add DataFunctionArgs type export into 6.4

[DaveLo]

What is the new or updated feature that you are suggesting?

I was following along with the getting started with Data example in the docs in typescript when I ran into a missing type for loader functions. It is working with inlined loaders so I wouldn't classify this as a bug, but is missing from the types export for react-router-dom

To demonstrate here is a sandbox where I define an empty loader inline and can see the type info, but can't add that same type to my loader directly.

Why should this feature be included?

This should be included for improved DX in typescript apps

[brophdawg11]

Fixed in #8975 - will be released with the next prerelease