Initiates fading out of the GameTooltip over the next few seconds.
Note: the game itself does not call this method to fade out the tooltips, although the effect is similar.
Once this method has been called, the GameTooltip will remain at full opacity for one second before fading out over another second and eventually hiding itself. However, if the
GameTooltip:Show() method is called while the tooltip is fading out, the fade will be aborted and the tooltip will return to full opacity.
If you must resize a GameTooltip while it is fading and don't want to cancel the fade by calling GameTooltip:Show(), use the following:
GameTooltip:AppendText( "" )