There's a lot of demand for vue sfc (#2097). This introduces partial support for them: all the html is printed as is, except for the script and style tags which are printed using prettier. I believe that this should cover a lot of the use cases while being simple to support and if we want we can extend to more in the future.
I copy pasted the html parser used by vue (it's just a single 400 lines file) so that we don't run the chancesof conflicts. I'm also very conservative: I only print the style and script at the top level and for the lang attributes we support.
I expect this to be landable as is and provide value, review welcome :)
Jed Fox