Add support for Svelte.js

[benwoodward]

Just duplicated the Vue.js configs. Seems to work.

[AndrewRadev]

I'm not very familiar with Svelte, but I can see that it's similar to Vue in expecting script and style tags and HTML in one file. So I can see how it would work. I'm happy to include it.

That said, what do you think about directly including the vue.js support file instead? So, instead of that code, this should work the same way:

runtime ftplugin/vue/splitjoin.vim

The benefit is if any more Vue support is added, or if the callbacks are reordered to fix a bug, Svelte should work the same way. The drawback is that if we ever want to add Svelte-specific support, we'd have to go back to copy-pasting the code, but then we'd be in the same position anyway.

What do you think?

[benwoodward]

Yep, makes a lot of sense. Tested it, works, made a commit.

[AndrewRadev]

Thanks, I'll go ahead and merge then 👍