chore: update js-doc throughout the app, batch 1

[kieckhafer]

Resolves parts of #5269 & #5267
Impact: major
Type: docs|chore

Issue

We are missing entire jsdoc blocks in some instances, and param / return / description lines of jsdoc in other instances, along with other jsdoc errors, all throughout Reaction. This is the biggest contributor to our eslint warnings.

Solution

Add / fix jsdoc where necessary.
Since there are so many of these warnings, I'm going to split it up into multiple PR's to keep the file count low for easier viewing / less conflicts with open branches.

Breaking changes

None

Testing

1. Start the app
2. Make sure it runs
3. All changes are documentation changes, there should be no effect on the app in general

More detail for what each of these sections should include are available in our Contributing Docs

[von-steinkirch]

Erik, I run your branch and the warnings are down to 417! Almost half, very cool.

[von-steinkirch]

Hi, curious what's the meaning of this change (and what does having "_" mean).

[kieckhafer]

@bt3gl we have all our queries / mutations set up to accept these three params: parentResult, inputArgs, and context. In a lot of cases, we don't need to pass in parentResult or any args, so we use _ and __ as placeholders for these fields.