- Add a signal DUChain::declarationSelected, that can be triggered by any party to indicate that the declaration has been selected somewhere in the user-interface.
- Trigger that signal when a completion-item has been selected in the completion-list
- Wait for the signal in the context-browser, highlightight such selected declarations uses in the document, and show information about them in the context-browser.

This is a nice effect for code-completion on local declarations, and makes it possible to conveniently see more information about items in the completion-list without using the small embedded navigation-widget.