theme: sweep everything that isnt using a spacing token from singleton,

add Theme.XXS

quickshell/Modules/Notifications/Center/NotificationKeyboardHints.qml

@@ -20,7 +20,7 @@ Rectangle {
         anchors.left: parent.left
         anchors.right: parent.right
         anchors.margins: Theme.spacingS
-        spacing: 2
+        spacing: Theme.spacingXXS
 
         StyledText {
             text: I18n.tr("↑/↓: Nav • Space: Expand • Enter: Action/Expand • E: Text")

quickshell/Modules/Notifications/Center/NotificationSettings.qml

@@ -248,7 +248,7 @@ Rectangle {
                     }
 
                     Column {
-                        spacing: 2
+                        spacing: Theme.spacingXXS
                         anchors.verticalCenter: parent.verticalCenter
                         width: overlayRow.width - Theme.iconSizeSmall - Theme.spacingM
 
@@ -299,7 +299,7 @@ Rectangle {
                     }
 
                     Column {
-                        spacing: 2
+                        spacing: Theme.spacingXXS
                         anchors.verticalCenter: parent.verticalCenter
                         width: privacyRow.width - Theme.iconSizeSmall - Theme.spacingM