Fixes#120217 where releasing both left and right shift keys
simultaneously would result in one of the shift keys not receiving the
KEYUP event. Previously an edge case was implemented that handled
shift key release with WM_INPUT for when a shift key was released while
the other was held. This change would handle all shift key release with
WM_INPUT instead of partially with WM_INPUT and partially with WM_KEYUP
for consistent handling.
jack-klein-5
1d9f732bc4