Inaccuracy: duplicate `id` in getting started with aria `code` example

Created by: kameronahler

Summary

I believe the Getting Started with ARIA article has a duplicate id in the "Role, state, and property together in a Tab control" section's code example.

Expected

  <div role="tablist">
    <button role="tab" aria-selected="true" aria-controls="panel_1">Apples</button>
	
    <!-- the proceeding button should correspond with an element with an id of panel_2 -->
    <button role="tab" aria-selected="false" aria-controls="panel_2" tabindex="-1">Oranges</button>
  </div>
  <div id="panel_1" aria-label="Apples" role="tabpanel" tabindex="0">...</div>
  
  <!-- presumably the following element -->
  <div id="panel_2" aria-label="Oranges" role="tabpanel" hidden>...</div>

Actual

  <div role="tablist">
    <button role="tab" aria-selected="true" aria-controls="panel_1">Apples</button>
    <button role="tab" aria-selected="false" aria-controls="panel_2" tabindex="-1">Oranges</button>
  </div>
  <div id="panel_1" aria-label="Apples" role="tabpanel" tabindex="0">...</div>
  <div id="panel_1" aria-label="Oranges" role="tabpanel" hidden>...</div>