Apply [] syntax for optional params to JSDoc @param tags

[MajorLift]

• It can be tricky to tell whether or not a parameter is optional if they are passed in as object properties that might also be nested.
• The JSDoc [] syntax gives a simple but clear visual indication of which params are optional.
• This PR annotates all existing params that are defined using the ?: operator.

[mcmire]

I noticed you suggested these changes on #157. In the extension and mobile app you may see this technique, but that's because most of the files are still written using JavaScript. However, in projects that use TypeScript, we've stopped using it, because now any information related to types can be gleaned from TypeScript.

This is further explained by looking at where JSDoc is used:

1. When writing code (i.e. hovering on a symbol). In this case, VSCode seems to ignore brackets around arguments. If you hover over a function, it doesn't show types for arguments at all; if you hover over an argument, it'll show you the type (which you specify separately).
2. When viewing generated documentation. We use typedoc to generate documentation, and this tool does not read the brackets around arguments.
3. When reading code. I guess looking over your PR description, that seems to be the main argument for adding this change. If you want to know whether an argument for a function is optional, though, I'm wondering if it's enough to look at the TypeScript types?

[MajorLift]

I think the brackets might still be useful when function params are passed in as objects, and those types have nested optional properties.

For example, if we were to add a nested entry into ValidateChangeLogOptions like packageRename?: PackageRenameOptions and some properties of PackageRenameOptions were optional, JSDoc [] syntax highlighting makes it easy to identify the optional arguments at a glance, without having to click and hover our way through multiple types.

I guess the utility of doing this for all typescript projects is limited, though, if the language server and docgen don't utilize the brackets. Just stating "optional" in human language like we're doing now might be good enough.

[mcmire]

Yeah. I mean, it's a good thought.

If you keep running into this and still think it would be valuable, I wonder if it would be better to find or add an ESLint rule around this so it could automatically add the brackets and they would be present without us having to think about it.

[MajorLift]

It seems like there are no eslint rules for optional @param or @property tags, at least in eslint-plugin-jsdoc. I guess we could add the brackets if we come across a situation where they'd be especially useful, without enforcing consistent usage everywhere.

Closing this PR for now. Will revert b51a4fa as well.