Add help modal for keyboard shortcuts. (#3033)

* Add help modal for keyboard shortcuts.

* add release note

* fix linter

* fix typecheck

* fix linter

* use component syntax for GroupHeading

* use component syntax for Shortcut

* fix linter

* use component syntax for KeyIcon

* refactor to support different dialogs

* show different help based on current page

* fix linter

* reword help

* capitalize letters

* show cmd on mac

* stop event propagation

* dont show if a modal is already open

* remove unused import

* rename modal

* move where location check happens

* dont stop event

* allow typing '?' in inputs

* better filter

* extract function

* fix linter

* dont show if filter popover is visible

* fix linter

* fix wrong shortcut, support SHIFT

* fix linter

* fix conditional