Document API with JSDoc

[dsanders11]

There are a lot of (undocumented) comments in https://github.com/electron/fiddle-core/blob/main/etc/fiddle-core.api.md, we should add JSDoc strings to fully document the API and clear those out.

[abhishekgite446]

Opened a PR to address this issue :)

[hr188]

@dsanders11 can i work on this ?

[sharvitKashikar]

@dsanders11 I can work on this! assign this to me.
Thank you

[dsanders11]

@sharvitKashikar, we don't assign issues to external contributors, and you don't need to ask to work on any open issue. 👍

[sharvitKashikar]

@sharvitKashikar, we don't assign issues to external contributors, and you don't need to ask to work on any open issue. 👍

Got it, thanks for the clarification 👍

[shanu106]

can you assign this issue to me ? i want to work on this .