Allow Prettier to format JS generated in wasm projects (#196)

Right now I'm getting ESLint errors because wasm-lib generates a JS project with semicolons.
This didn't use to matter, because `yarn prettier` applied to the Rust projects too. But
in my recent PR https://github.com/KittyCAD/untitled-lang/pull/192 I broke that.

This should fix it by ensuring the generated JS code gets formatted in a way that matches
our ESLint requirements.

.prettierignore

@@ -3,4 +3,5 @@ build
 coverage
 
 # Ignore Rust projects:
-src/wasm-lib
+*.rs
+target