Bug: @snowpack/plugin-babel strips out extensions from processed files

[jonrimmer]

I'm trying to use the Babel plugin to process all files in my project with the extension: .styles.ts, in order to run babel-plugin-styled-components against them. However, if I have files called called app.tsx and app.styles.ts in my project, then running Babel on the latter produces a file called app.js which overrides the correct version.

This seems to be because the plugin is hardcoded to output .js files, and isn't smart enough to retain extra extensions.