fixes #4506: clearfix added to .dl-horizontal to account for empty dd elements

docs/assets/css/bootstrap.css

@@ -725,6 +725,21 @@ dd {
   margin-left: 10px;
 }
 
+.dl-horizontal {
+  *zoom: 1;
+}
+
+.dl-horizontal:before,
+.dl-horizontal:after {
+  display: table;
+  line-height: 0;
+  content: "";
+}
+
+.dl-horizontal:after {
+  clear: both;
+}
+
 .dl-horizontal dt {
   float: left;
   width: 120px;

less/type.less

@@ -116,6 +116,7 @@ dd {
 }
 // Horizontal layout (like forms)
 .dl-horizontal {
+  .clearfix(); // Ensure dl clears floats if empty dd elements present
   dt {
     float: left;
     width: 120px;