TypeScript

I recently found this package, and I'd like to say great job! but I've been working a lot and I recently moved my files to TypeScript instead of JS for error checking and auto-completion in this thing I'm making. If you could, could you also include .ts files with structure-view, perhaps similarly to JS? Would be great.

Start by locating how structure-view currently handles JavaScript files and builds their symbol tree. Determine the existing entry point and tests for JavaScript support, then add equivalent handling for .ts files; done when TypeScript files show the expected structure and support the same navigation behavior.

Written by the indexing model from the issue text.