Clarify parameters in AudioWorkletProcessor.process()

[hoch]

Currently the description says:
https://www.w3.org/TR/webaudio/#dom-audioworkletprocessor-process

A map of string keys and associated Float32Arrays. parameters["name"] corresponds to the automation values of the AudioParam named "name".

The term map here can be confusing, because this is not an ES6 Map. A set of key-value pairs, or we could say an "associative array".

[hoch]

Actually, we can simply use this link: https://infra.spec.whatwg.org/#maps

Also perhaps it's better to use the WebIDL Record type.