[FIX] ws doc: copy button in columned version

doc/_themes/odoodoc/static/style.css

@@ -7243,6 +7243,19 @@ td.field-body > ul {
   .stripe .highlight pre {
     white-space: pre-wrap;
   }
+  .stripe .btn-clipboard {
+    background-color: transparent;
+    color: #eeeeee;
+    border-color: #777777;
+    border-top: none;
+    border-top-right-radius: 0;
+  }
+  .stripe .btn-clipboard.active {
+    background-color: #555555;
+    -webkit-transition: background-color 0.5s linear;
+    -o-transition: background-color 0.5s linear;
+    transition: background-color 0.5s linear;
+  }
 }
 .stripe .switcher {
   color: white;

doc/_themes/odoodoc/static/style.less

@@ -760,6 +760,19 @@ td.field-body {
       // but allow additional line-breaks between "words" to avoid overflow
       white-space: pre-wrap;
     }
+
+    .btn-clipboard {
+      background-color: transparent;
+      color: @color-right;
+      border-color: @separator-right;
+      border-top: none;
+      border-top-right-radius: 0;
+
+      &.active {
+        background-color: @gray;
+        .transition(background-color .5s linear);
+      }
+    }
   }
 
   .switcher {