Improve the README

- Add a MELPA Stable badge
- Remove the unnecessary (require 'vue-mode) section
- Ensure elisp code is properly indented
- Clean up the spacemacs section
- Clean up the Q&A section
- Add a section or point about our new indirect editing functionality (`M-x vue-edit-indirect-at-point`)

Help on any of these points would be greatly appreciated.

Start by reading the README and reviewing its MELPA Stable, spacemacs, Q&A, and elisp sections. Check the existing indirect editing functionality and its command, `M-x vue-edit-indirect-at-point`; done means the listed README updates are complete, the unnecessary require section is removed, and the elisp examples are consistently indented.

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