next.js

3817770b - docs: update Route Handlers to have JS/TS code snippet. (#51003)

docs: update Route Handlers to have JS/TS code snippet. (#51003) Added a TS and JS switcher. Previously the code snippet did not have a switcher. The file extension was .js when the code was TypeScript which made it confusing to try to read. --------- Co-authored-by: Lee Robinson <me@leerob.io>