NLoader: renamed property panel => content so it looks more versatile

Modules/Background/ScreenCorners.qml

@@ -8,7 +8,7 @@ import qs.Widgets
 NLoader {
   isLoaded: Settings.data.general.showScreenCorners
 
-  panel: Variants {
+  content: Variants {
     model: Quickshell.screens
 
     PanelWindow {

Modules/DemoPanel/DemoPanel.qml

@@ -13,7 +13,7 @@ import qs.Widgets
 NLoader {
   id: root
 
-  panel: Component {
+  content: Component {
     NPanel {
       id: demoPanel
 

Modules/SidePanel/SidePanel.qml

@@ -29,7 +29,7 @@ NLoader {
     }
   }
 
-  panel: Component {
+  content: Component {
     NPanel {
       id: sidePanel