Naming difference: Spec *Factory.available() vs Explainer *Factory.availability()

[michaelwasserman]

Please help resolve the intended method name for checking availability from the factories.

The spec defines *Factory.available():
https://webmachinelearning.github.io/writing-assistance-apis/#ref-for-dom-aisummarizerfactory-available
https://webmachinelearning.github.io/writing-assistance-apis/#dom-aiwriterfactory-available
https://webmachinelearning.github.io/writing-assistance-apis/#dom-airewriterfactory-available

The explainer describes *Factory.availability():
https://github.com/webmachinelearning/writing-assistance-apis?tab=readme-ov-file#testing-available-options-before-creation

[domenic]

Oops! The intent is availability(), especially after #29 lands. I will fix the spec momentarily.