qml: Make annotations on CharKey appear larger to be more visible

Some keys have annotations that are quite difficult to discern in some
situations, so make the label for the annotation a little larger to more
easily read them in those cases.

qml/keys/CharKey.qml

@@ -177,7 +177,7 @@ Item {
                 anchors.top: parent.top
                 anchors.topMargin: Device.annotationTopMargin
                 anchors.rightMargin: Device.annotationRightMargin
-                font.pixelSize: key.fontSize / 3
+                font.pixelSize: key.fontSize / 2
                 font.weight: Font.Light
                 visible: !panel.hideKeyLabels
             }