[nodebb-plugin-mentions] Not compatible with all composers

[drew]

The mentions plugin only works with the default composer. Redactor would greatly benefit from mentions working, as I'm sure many future composer plugins would too.
https://github.com/julianlam/nodebb-plugin-mentions/issues/60
I assume it's got something to do with the classes it binds to, but can't be sure.

[exodo]

agreed, please @administrators make it happen