Automatically align => while typing or when saving

**Summary of the new feature**

Automatic => alignment, as I type, or when saving, or with a hotkey.

For example:

---
**As a** user

**I would like to** automatically automatically align `=>` as I type, or when saving, or with a hotkey.

**so that I** don't have to remember to do it myself or run lint, then go back and hit space/tab until all hashes are properly aligned.
