Revert "#4288 Remove auto Alt+Printscreen on Windows"

This reverts commit 3d3b7ca881.

src/lib/platform/MSWindowsKeyState.cpp

@@ -1075,6 +1075,11 @@ MSWindowsKeyState::getKeyMap(synergy::KeyMap& keyMap)
 			}
 		}
 
+		// add alt+printscreen
+		if (m_buttonToVK[0x54u] == 0) {
+			m_buttonToVK[0x54u] = VK_SNAPSHOT;
+		}
+
 		// set virtual key to button table
 		if (activeLayout == m_groups[g]) {
 			for (KeyButton i = 0; i < 512; ++i) {