Update configuration.md

Added `complete` event.
Replaced Goto UI with ACE's Popup with virtual rendered. Speeds up the
Goto UI _massively_ for bigger projects.
Added best feature ever: open the Zed project picker from with any Zed
edit window using `Command-Shift-O`/`Ctrl-Shift-O`.
Merge branch 'master' of github.com:zedapp/zed
No longer full-text search various known binary formats (zip, tar.gz
etc.)
Fix some minor bugs in split views as well as overflow handling in the
editbar (resulting in odd looking scrollbars when resizing the window).
Merge branch 'master' of github.com:/dsrw/zed into scott