Update for 0.18+

[ymtszw]

It looks like the repository is stale for quite some time, so let me ask for the status of this package.

There are several items for Elm 0.18+:

• Syntax updates
• Dropping elm-oracle support since it is no longer compatible (elmjutsu is actively updated and works great. Good replacement)

I am actually doing these in my fork (https://github.com/ymtszw/language-elm), so if some collaborators can handle PRs, I would like to. Although now the fork is quite large, it may take some time.

Also, I myself is (at least for now) actively using Atom for Elm development, so I would like to offer my hands for maintenance of the package, if existing members cannot afford their time. ❤️

Hope someone notices this!