WelcomePage: pixel perfection on Mac

We have to vertical align the text.

Change-Id: I96fa4f410c629d3b7beb4b9a19cbda3e54a63058
Reviewed-by: Virva Auvinen <virva.auvinen@nokia.com>
Reviewed-by: Alessandro Portale <alessandro.portale@nokia.com>

share/qtcreator/welcomescreen/widgets/LinkedText.qml

@@ -37,6 +37,7 @@ Text {
     id: root
     height: 16
     color: active ? "#f0f0f0" : colors.linkColor
+    verticalAlignment: Text.AlignVCenter
 
     font: fonts.linkFont