Make it possible to transpose selection by +6/-6 semitones

Author: juzzlin

src/view/qml/Editor/MainContextMenu.qml

@@ -394,6 +394,16 @@ Menu {
             enabled: !UiService.isPlaying()
             onTriggered: editorService.requestSelectionTranspose(-2)
         }
+        Action {
+            text: qsTr("Transpose <b>+6</b> semitones")
+            enabled: !UiService.isPlaying()
+            onTriggered: editorService.requestSelectionTranspose(6)
+        }
+        Action {
+            text: qsTr("Transpose <b>-6</b> semitones")
+            enabled: !UiService.isPlaying()
+            onTriggered: editorService.requestSelectionTranspose(-6)
+        }
         Action {
             text: qsTr("Transpose <b>+12</b> semitones")
             shortcut: "Alt+Shift+F12"