Topic watching change

[baris]

Please see https://github.com/NodeBB/NodeBB/pull/4662

If you have a custom theme that has a partials/topic/watch.tpl you will need to update it for 1.1.0.

You can see the changes you need to make in https://github.com/NodeBB/nodebb-theme-persona/pull/278/files

Persona, vanilla and lavender themes are already updated.