Documentation: Default form style does not support label fully

[JensRantil]

http://twitter.github.io/bootstrap/base-css.html#forms says the default for style is:

<form>
  <fieldset>
    <legend>Legend</legend>
    <label>Label name</label>
    <input type="text" placeholder="Type something…">
    <span class="help-block">Example block-level help text here.</span>
    <label class="checkbox">
      <input type="checkbox"> Check me out
    </label>
    <button type="submit" class="btn">Submit</button>
  </fieldset>
</form>

I propose the example is extended so

• that the <input> is given an id attribute; and
• the <label> tag also includes an for attribute that is bound to the input.

This will make the label clickable and improve usability.

[mdo]

Fixed in v3.