docs(input): remove redundant closing span tag

Closes angular#5257

Author: miknsh5

src/ng/directive/input.js

@@ -1432,7 +1432,6 @@ var CONSTANT_VALUE_REGEXP = /^(true|false|\d+)$/;
                      id="{{name}}"
                      name="favorite">
             </label>
-          </span>
           <div>You chose {{my.favorite}}</div>
         </form>
       </doc:source>