Improve calqlatr accessibility

Add accessibility annotations to make the screen readers
read out the content correctly. For instance, VoiceOver
on macOS reads "x²" as "x two", where it should be "x
squared". Also give a more descriptive accessible name to
the somewhat unfortunately named "BS" button.

The Text items in the Display also need Accessible.name,
since Text is a low-level item which do not provide
a11y content by itself.

Fix issue with handling the Press action: the a11y system
does not call the mouse "press" or "release" signals in response
to this action, use "clicked" instead.

Pick-to: 6.10
Change-Id: I9c4cccf1b60c55320a149f97c86edea92a47bbb5
Reviewed-by: Oliver Eftevaag <oliver.eftevaag@qt.io>
Reviewed-by: Konsta Alajärvi <konsta.alajarvi@qt.io>
Reviewed-by: Rami Potinkara <rami.potinkara@qt.io>

examples/demos/calqlatr/content/BackspaceButton.qml

@@ -16,6 +16,7 @@ RoundButton {
     // include this text property as the calculator engine
     // differentiates buttons through text. The text is never drawn.
     text: "bs"
+    Accessible.name: "backspace"
 
     property bool dimmable: true
     property bool dimmed: false
@@ -56,7 +57,7 @@ RoundButton {
         return "images/backspace.svg";
     }
 
-    onReleased: {
+    onClicked: {
         root.operatorPressed("bs");
         updateDimmed();
     }

examples/demos/calqlatr/content/Display.qml

@@ -160,12 +160,14 @@ Item {
                         font.pixelSize: display.fontSize
                         color: display.qtGreenColor
                         text: parent.operator
+                        Accessible.name: parent.operator
                     }
                     Text {
                         font.pixelSize: display.fontSize
                         anchors.right: parent.right
                         anchors.rightMargin: 16
                         text: parent.operand
+                        Accessible.name: parent.operand
                         color: "white"
                     }
                 }

examples/demos/calqlatr/content/NumberPad.qml

@@ -31,14 +31,14 @@ Item {
     }
 
     component DigitButton: CalculatorButton {
-        onReleased: {
+        onClicked: {
             root.digitPressed(text);
             updateDimmed();
         }
     }
 
     component OperatorButton: CalculatorButton {
-        onReleased: {
+        onClicked: {
             root.operatorPressed(text);
             updateDimmed();
         }
@@ -65,14 +65,32 @@ Item {
                 rowSpacing: controller.spacing
                 visible: !isPortraitMode
 
-                OperatorButton { text: "x²" }
-                OperatorButton { text: "⅟x" }
+                OperatorButton {
+                    text: "x²"
+                    Accessible.name: "x squared"
+                }
+                OperatorButton {
+                    text: "⅟x"
+                    Accessible.name: "one over x"
+                }
                 OperatorButton { text: "√" }
-                OperatorButton { text: "x³" }
-                OperatorButton { text: "sin" }
-                OperatorButton { text: "|x|" }
+                OperatorButton {
+                    text: "x³"
+                    Accessible.name: "x cubed"
+                }
+                OperatorButton {
+                    text: "sin"
+                    Accessible.name: "sine"
+                }
+                OperatorButton {
+                    text: "|x|"
+                    Accessible.name: "absolute value"
+                }
                 OperatorButton { text: "log" }
-                OperatorButton { text: "cos" }
+                OperatorButton {
+                    text: "cos"
+                    Accessible.name: "cosine"
+                }
                 DigitButton {
                     text: "e"
                     dimmable: true