Add get_url to Documentation

[hugetim]

For reference:

[SOLVED] PDF Media Files not previewing in browser

By default, if you get the url from a Media object in a data table, it’s set up for download (Content-Disposition: attachment). You can create an HTTP endpoint that serves up the file without that header (the opposite of @neriksen85’s question here). Or, instead of the url property, you can use the (ahem, undocumented) method get_url(False), which gets the non-auto-downloading version.

And to confirm it’s still undocumented (as of this posting):
https://anvil.works/docs/api/anvil#Media