docs: update mkdocs settings to allow copying blocks of code / downloading URL-based snippets

[hollandjg]

Description

Update the documentation:

• Allow copying blocks of code in the browser
• Allow including snippets specified by URL

Required to merge https://github.com/AutoResearch/autora-workflow/pull/44

Type of change

Delete as appropriate:

• docs: Documentation only changes

Screenshots (Optional)

Copy code blocks

Include snippets by URL:

This in the input file:

...leads to this in the documentation: