onThese and other functions in EventM are not exported

[zopa]

Several functions in GHCJS.DOM.EventM trigger -Wunused-top-binds. The one that interests me is onThese, which looks useful, but we might as well deal with the rest while I'm at it.

I'm happy to submit a pull request, but I thought I'd check if any of these should be removed rather than exported.

I assume the way to proceed is to submit patches to both jsaddle-dom and this repository, and bump the minor version numbers and constraints?

The functions at issue (from GHCJS/DOM/EventM.hs):

• onThese
• eventTargetUnsafe
• eventTargetUnchecked
• targetUnsafe
• targetUnchecked
• eventCurrentTargetUnsafe
• eventCurrentTargetUnchecked