Biquad doesn't exist in OpenProcessing / bad help article

Hi, there's a page on p5.Biquad filters in the documentation -
https://p5js.org/reference/p5.sound/p5.Biquad/
BUT that page doesn't actually use the Biquad constructor, it uses Bandpass.
See the line:
`filterEffect = new p5.BandPass();`
There are other pages which use Biquad:
https://p5js.org/reference/p5.Biquad/gain/
However, OpenProcessing shows an error when you try to set up a Biquad filter -
`sinFilter = new p5.Biquad(8000, "highshelf");`
- this gives the error _p5.Biquad is not a constructor_
It looks like Biquad doesn't actually exist in P5. So, we need to amend the documentation.
Thanks

Start with the p5.Biquad reference page and its gain reference page, then compare the documented constructors with the filter APIs available in p5.sound.js. Update the affected documentation and examples so they no longer present p5.Biquad as an available constructor, and verify that the corrected pages match the API used by OpenProcessing.

Written by the indexing model from the issue text.