vim: add signal to jump to keyword documentation.
workspace: remove devhelp workspace
grid: add helper to find a tab of certain type
devhelp: use devhelp assistant for now for devhelp tab
editor: SHIFT+K in VIM will now jump to documentation for keyword

This should be somewhat like VIM but use a secondary pane for the info.
We might consider using the same pane and just CTRL+W to dismiss it.