LiquidDoc linters should report unused parameters

[karreiro]

Is your feature request related to a problem? Please describe.

I would like to add a linter rule that detects parameters documented in Liquid files with {% doc %} that are never actually passed in any of the calls to the snippet across the codebase.

For example, consider this snippets/example.liquid:

{%- doc -%}
  Renders a card for displaying various resource types (products, collections, articles, pages).

  @param {object} resource - The resource to render
  @param {string} [style] - The style of the card. Can be 'default' or 'overlay'
{%- enddoc -%}
...

This example has an optional style parameter, and there might be code related to it. However, if no one ever renders snippets/example.liquid with the style parameter, we should lint for it. This could be an opportunity to refactor and simplify snippets/example.liquid.

Describe the solution you'd like

I'd like a new linter check to cover the case described above.