Qt: controlbar: add tooltip and fix idle A-B loop colors

modules/gui/qt/player/qml/controlbarcontrols/AtoBButton.qml

@@ -26,13 +26,15 @@ import VLC.Util
 Widgets.ImageToolButton {
     id: control
 
-    text: qsTr("A to B")
+    text: qsTr("A to B Loop")
 
     sourceSize: Qt.size(VLCStyle.icon_toolbar, VLCStyle.icon_toolbar)
 
     checked: Player.ABloopState !== Player.ABLOOP_STATE_NONE
     onClicked: Player.toggleABloopState()
 
+    description: text
+
     //imageSource: "qrc:///icons/atob.svg"
     imageSource: {
         switch(Player.ABloopState) {

modules/gui/qt/widgets/qml/ImageToolButton.qml

@@ -29,6 +29,8 @@ T.ToolButton {
 
     property url imageSource: ""
 
+    property string description
+
     property bool paintOnly: false
 
     property size sourceSize: Qt.size(VLCStyle.icon_normal, VLCStyle.icon_normal)
@@ -47,6 +49,12 @@ T.ToolButton {
 
     //Accessible
     Accessible.onPressAction: control.clicked()
+    Accessible.name: description
+
+    // Tooltip
+    T.ToolTip.visible: (hovered || visualFocus)
+    T.ToolTip.delay: VLCStyle.delayToolTipAppear
+    T.ToolTip.text: description
 
     readonly property ColorContext colorContext: ColorContext {
         id: theme