Keyboard navigation through Todos

Description

I want to navigate through my todos using the keyboard.

Proposal

Allow navigating through my todos with j k and ENTER.

Links / references

cc @victorwu @jschatz1

Documentation blurb

(Write the start of the documentation of this feature here, include:

1. Why should someone use it; what's the underlying problem.
2. What is the solution.
3. How does someone use this

During implementation, this can then be copied and used as a starter for the documentation.)