import fix / autocomplete requires type checking JS/JSX

Extracted issue from https://code.visualstudio.com/docs/nodejs/working-with-javascript#_type-checking-javascript

Auto complete of imports in JS/JSX files does not work properly unless type checking of JS/JSX files is explicitly enabled. This is counter intuitive, and forces the user to endure potentially unwanted type errors in order to have working autocomplete of imports.

It's extra confusing because the autocomplete does work for symbols exported from modules that are already imported (so it seems like it should work but is flaky). It took me a long time to find this problem.

Comienza con la documentación enlazada de TypeScript sobre la comprobación de tipos de JavaScript y reproduce la autocompletación de imports en JS/JSX con la comprobación de tipos deshabilitada. Rastrea el comportamiento del language service para los imports y compáralo con los símbolos de los módulos ya importados. Se considera completado cuando la autocompletación de imports funciona sin requerir la comprobación de tipos ni producir errores de tipos no deseados.