Adwaita: Update rubberband styling

Adapt to the changes in the previous commit.

gtk/theme/Adwaita/_common.scss

@@ -120,7 +120,8 @@ textview text,
   }
 }
 
-.rubberband {
+.rubberband,
+rubberband {
   border: 1px solid darken($selected_bg_color, 10%);
   background-color: transparentize(darken($selected_bg_color, 10%), 0.8);
 }
@@ -1269,7 +1270,7 @@ treeview.view {
   border-left-color: mix($fg_color, $base_color, 50%); // this is actually the tree lines color,
   border-top-color: $bg_color;                         // while this is the grid lines color, better then nothing
 
-  &.rubberband { @extend .rubberband; } // to avoid borders being overridden by the previously set props
+  &.rubberband { @extend rubberband; } // to avoid borders being overridden by the previously set props
 
   &:selected { border-radius: 0; } // rest border radius in lists
 
@@ -3195,7 +3196,7 @@ colorswatch {
   background-color: darken($bg_color,7%);
   &:hover { -gtk-image-effect: highlight; }
   &:backdrop { background-color: darken($bg_color,7%); }
-  &.rubberband { @extend .rubberband; }
+  & rubberband { @extend rubberband; }
 }
 
 .scale-popup {

gtk/theme/Adwaita/gtk-contained-dark.css

@@ -77,7 +77,10 @@ textview text,
   calendar:selected {
     border-radius: 3px; }
 
-.rubberband, treeview.view.rubberband, .content-view.rubberband {
+.rubberband,
+rubberband,
+treeview.view.rubberband,
+.content-view rubberband {
   border: 1px solid #184472;
   background-color: rgba(24, 68, 114, 0.2); }
 

gtk/theme/Adwaita/gtk-contained.css

@@ -77,7 +77,10 @@ textview text,
   calendar:selected {
     border-radius: 3px; }
 
-.rubberband, treeview.view.rubberband, .content-view.rubberband {
+.rubberband,
+rubberband,
+treeview.view.rubberband,
+.content-view rubberband {
   border: 1px solid #2a76c6;
   background-color: rgba(42, 118, 198, 0.2); }