Add a clear, obvious way to remove hotkeys to improve UX

[Hermanio]

I find that there should be some obvious way to remove a hotkey, like a red cross next to the set hotkey to remove it. Pressing escape in a situation where backspace or delete does not remove the hotkey is not intuitive at all, especially to a new user.

What I ended up doing (but not something that a normal user would do) was going to the configuration folder of this program and finding the json file containing the hotkey bindings, where I could finally set it to null again.

Take for example GNOME 3 settings.

The red cross near the set hotkey is a clear indication that you can remove the hotkey by clicking on the cross.

Here is an example of what it should look like (example taken from Polymer paper-input element demo):

What this view currently looks like to me:

What it could look like (but prettier):

[welcome]

👋 Thanks for opening your first issue here! If you're reporting a 🐞 bug, please make sure you include steps to reproduce it. We get a lot of duplicate issues on this repo, so please double check now that your issue has not already been solved or doesn't have an open issue already.
To help make it easier for us to investigate your issue, please follow the contributing guidelines and ensure the issue template was filled out.

[jostrander]

Makes sense. There is nothing denoting escape as the way to unset a hotkey, so having that and/or the X (albeit maybe not red). PR's welcome.

[MarshallOfSound]

Fixed in master