Add note about how to view trashed notes.

[samuelallan72]

Currently possible by searching for tag:trash. Should be more visible, or at least documented.

[pataquets]

In addition to documenting, maybe stating somewhere that trashing is done by tagging as trash, eg. in the keys help screen text: Trash note (tag with 'trash'). Would make it more discoverable, as one might guess that searching for it would work.