Update docs with changes from implementing Action IDs (#790)

Updates the docs page for Actions with the following changes:

- The actions examples now no longer contain keybindings
- The removed keybindings have now been moved to their own section where
they refer to said actions by ID
- The list of all the available commands/actions now shows both the
default ID for the in-built actions as well as their default keybindings

Author: PankajBhojwani