Remove border on fixed menu

src/definitions/collections/menu.less

@@ -1625,7 +1625,13 @@ Floated Menu / Item
   right: auto;
   bottom: auto;
 }
+.ui[class*="top fixed"].menu {
+  border-left: none;
+  border-right: none;
+}
 .ui[class*="right fixed"].menu {
+  border-top: none;
+  border-bottom: none;
   border-right: none;
   top: 0px;
   right: 0px;
@@ -1636,12 +1642,16 @@ Floated Menu / Item
 }
 .ui[class*="bottom fixed"].menu {
   border-bottom: none;
+  border-left: none;
+  border-right: none;
   bottom: 0px;
   left: 0px;
   top: auto;
   right: auto;
 }
 .ui[class*="left fixed"].menu {
+  border-top: none;
+  border-bottom: none;
   border-left: none;
   top: 0px;
   left: 0px;