Move focus between panes with keyboard

Shortcuts for moving focus across panes.
Compatible with vim plugin.

".CodeMirror.vim-mode.normal-mode textarea":
  "s h": "core:focus-note-list-bar"
  "s k": "editor:title:focus"
".sidebar-menu":
  "s l": "core:focus-note-list-bar"
".sidebar-book-filter-menu":
  "s l": "core:focus-note-list-bar"
".note-list-bar":
  "s l": "editor:focus"
  "s h": "core:sidebar-focus"
".mde-preview":
  "s h": "core:focus-note-list-bar"
  "s k": "editor:title:focus"