Add support for offsetX and offsetY in MouseEvent

[singpolyma]

No description provided.

[JordanMartinez]

You might want to see #2...

[singpolyma]

@JordanMartinez these days it seems it is standardized: https://web.archive.org/web/20200919224107/https://drafts.csswg.org/cssom-view/#extensions-to-the-mouseevent-interface

[hdgarrood]

Since it's part of the CSSOM spec I think the best place for these is probably the web-cssom library.

[singpolyma]

@hdgarrood could do that... how should that look, just a module with the same name as here but under the CSSOM hierarchy that exports the offset functions?

[hdgarrood]

I'm not certain since I don't actually have too much involvement in the maintenance of these libraries, but yeah, I think Web.CSSOM.MouseEvent sounds reasonable.

[singpolyma]

Ok, alternate now here: purescript-web/purescript-web-cssom#5

[thomashoneyman]

I've approved purescript-web/purescript-web-cssom#5, so this can be closed.