title: Peek definition (Alt+F12) no longer does anything in Visual Studio
body: <p>While <code>Goto Definition</code> works as expected with key <kbd>F12</kbd>,<br />
  the hotkey <kbd>Alt</kbd>+<kbd>F12</kbd> for <code>Peek Definition</code> no longer does anything.<br />
  How do I restore <kbd>Alt</kbd>+<kbd>F12</kbd> functionality?</p>