Fix validation errors.

docs/components/dropdowns.md

@@ -34,10 +34,10 @@ You can optionally use `<button>` elements in your dropdowns instead of `<a>`s.
 
 {% example html %}
 <div class="dropdown open">
-  <button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenu1" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
+  <button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenu2" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
     Dropdown
   </button>
-  <div class="dropdown-menu" aria-labelledby="dropdownMenu1">
+  <div class="dropdown-menu" aria-labelledby="dropdownMenu2">
     <button class="dropdown-item" type="button">Action</button>
     <button class="dropdown-item" type="button">Another action</button>
     <button class="dropdown-item" type="button">Something else here</button>