Keybinding support for notepad

Created by: benvenker

Keybindings to support

So far, we've identified several:

- [ ] a: Add selected range in file or search result OR, if nothing selected add search or add file (from search results or file page), depending on context Had to change a: above because of some technical issues around there almost always being a line selected. Instead, we're going to give users a choice of whether to add the file or the selected range. There will be a UI affordance for this, but also key commands, below:

• a[s, f]: "a" will not be a precursor keybinding that will signal the user wants to copy a file results OR a file range (we can't know which easily). a -> f will save the file, a -> r will save the range
• d: Delete selected inbox items
• i: Focus top Inbox item
• t (or right arrow on selected, left arrow to close): open annotation box of focused item
• Shift+Left click: Select a range of Inbox items
• Cmd+Left Click: Select/deselect individual Inbox items
• e: toggle stack open or closed
• Add key commands to key command menu (triggered on shift + ? on .com)