Enable selectionStart/End on HtmlTextAreaElement

[wayeast]

Motivation

Wasm calls to these JS functions would be very handy!

Proposed Solution

Uncomment the block here.

Additional Context

Hello wasm-bindgen maintainers. I just wanted to see if there was a good reason why these two functions are still prevented from being implemented in web-sys (?). It looks like (the?) one compelling reason was lack of support for Option<u32> and the like in WebIDL (this issue), but this appears to have been resolved already here. Are these just the victims of oversight, or is there something else preventing them from being included in the crate? Many thanks.

[fitzgen]

Yeah, I think this is just an oversight -- want to submit a PR?

[wayeast]

@fitzgen #1533 Thanks!

[ibaryshnikov]

@fitzgen this may probably be closed since the merge of #1533?

[alexcrichton]

indeed thanks!