Telegram backend formatting

[fernand0]

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I am...

• [ ] Reporting a bug
• [X] Suggesting a new feature
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I am running...

• Errbot version: 6.1.1
• OS version: Ubuntu
• Python version: 3.6.6
• Using a virtual environment: yes

Issue description

I'm a happy user of telegram backend. Telegram uses a non-mono spaced font so when showing the result for some formatted commands the output is not well formatted (for example status command). Telegram allows for the use of markdown to indicate mono space fonts (```) but I'm not sure what would be the best way to make this available to errbot.

It would be nice to have this behavior available, at least, for some commands.