Remove uncessary `col-form-label` from form row docs (#24335)

docs/4.0/components/forms.md

@@ -314,36 +314,36 @@ More complex layouts can also be created with the grid system.
 <form>
   <div class="form-row">
     <div class="form-group col-md-6">
-      <label for="inputEmail4" class="col-form-label">Email</label>
+      <label for="inputEmail4">Email</label>
       <input type="email" class="form-control" id="inputEmail4" placeholder="Email">
     </div>
     <div class="form-group col-md-6">
-      <label for="inputPassword4" class="col-form-label">Password</label>
+      <label for="inputPassword4">Password</label>
       <input type="password" class="form-control" id="inputPassword4" placeholder="Password">
     </div>
   </div>
   <div class="form-group">
-    <label for="inputAddress" class="col-form-label">Address</label>
+    <label for="inputAddress">Address</label>
     <input type="text" class="form-control" id="inputAddress" placeholder="1234 Main St">
   </div>
   <div class="form-group">
-    <label for="inputAddress2" class="col-form-label">Address 2</label>
+    <label for="inputAddress2">Address 2</label>
     <input type="text" class="form-control" id="inputAddress2" placeholder="Apartment, studio, or floor">
   </div>
   <div class="form-row">
     <div class="form-group col-md-6">
-      <label for="inputCity" class="col-form-label">City</label>
+      <label for="inputCity">City</label>
       <input type="text" class="form-control" id="inputCity">
     </div>
     <div class="form-group col-md-4">
-      <label for="inputState" class="col-form-label">State</label>
+      <label for="inputState">State</label>
       <select id="inputState" class="form-control">
         <option selected>Choose...</option>
         <option>...</option>
       </select>
     </div>
     <div class="form-group col-md-2">
-      <label for="inputZip" class="col-form-label">Zip</label>
+      <label for="inputZip">Zip</label>
       <input type="text" class="form-control" id="inputZip">
     </div>
   </div>