title: How build a conversation handler with CllbackQueryHandler in it
body: <p><em>NB: I use version 12 of python-telegram-bot package.</em></p>
  
  <p>I would like to build a conversation handler: when  a user chooses \charts command, the bot shows them an inline list of choices, and depending on their choice, return them a chart.</p>
  
  <pre><code>charts_handler = ConversationHandler(
      entry_points=[CommandHandler('chart', chart_start)],
      states={
          ChartChoices.choosing_user: [CallbackQueryHandler(
              individual_chart,
              pass_user_data=True)
          ],
      },
      fallbacks=[done_handler],
  )
  </code></pre>
  
  <p>But if I do not set <code>per_message=False</code> then it results in this error:</p>
  
  <pre><code>If 'per_message=False', 'CallbackQueryHandler' will not be tracked for every message.
  </code></pre>
  
  <p>If I do set <code>per_message=True</code>, then it results in the error:</p>
  
  <pre><code>If 'per_message=True', all entry points and state handlers                                      
  must be 'CallbackQueryHandler', since no other handlers have a message context.
  </code></pre>
  
  <p>So it seems that the only way to build a conversation handler with CallBackQueryHandler (or in other words to show inline keyboard during chat) is to set all handlers to CallbackQueryHandler. Is it correct? </p>