Alert used to Notify AutoComplete Support?

[sam (Sam Saffron)]

Cleaned up per:

Error when opening user preferences while post editor is visible

On the upside this did catch a pretty ugly bug… nonetheless fixed per https://github.com/discourse/discourse/commit/6d22354ac338fa9a98e89c67054abd77fad1c8fb https://github.com/discourse/discourse-tagging/commit/abec4de26b3bf3d42d18b26b1c9f50d2f2c0b6a4