Enable Escape key to close tag suggestion popup
Enable Escape key to close tag suggestion popup

closes #1893
- Checking the contents of search term after evaluating the keycode caused the suggestion box to be hidden and immediately reshown
- Moving the if/else to the top of the function enables us to fix the issue without complicating the suggestion update logic

JohnONolan/Ghost-Admin,kevinansfield/Ghost-Admin,acburdine/Ghost-Admin,airycanon/Ghost-Admin,dbalders/Ghost-Admin,dbalders/Ghost-Admin,airycanon/Ghost-Admin,JohnONolan/Ghost-Admin,TryGhost/Ghost-Admin,kevinansfield/Ghost-Admin,TryGhost/Ghost-Admin,acburdine/Ghost-Admin