Add Render utility for recreating HTML or Markdown formatted text

[YouKnow-sys]

it would be nice and useful to have a utility to render a message text with its entities back to html or markdown so its something human readable and easier to store, right now if user want to store a formatted message text for later use they have to store both the text and entities separately and later on construct the message again which isn't ideal.
almost all other telegram libraries already have this feature, I'll include a link to some of their implementation below:

• teloxide: render.rs
• aiogram: formatting.py