Command palette should show first entry as selected

[plafosse]

Though just hitting enter from the command palette activates the first entry, we should allow actually show the first entry as highlighted as if you had just pressed down. This should provide better visual indication that hitting enter will do what you want.

Like this instead of the above:

[psifertex]

I looked into this some and while you can force the entry to actually be selected after every keystroke it results in really awkward usage since that requires de-selecting the text-field which means things like CTL-A to select all text won't work. If you start typing it can re-focus the edit box but again, if you're automatically focusing the first entry you'll run into the same problem.

It may be possible "fake" the selection of the first item when none has actually been selected but then that will also require making the first "down" arrow actually navigate down twice. AKA, this is potentially more complicated than it seems at first.