Auto-generate plugin options documentation

[michaelpj]

At the moment we have a hand-written section that lists some of the plugin options. This is not accurate, and it's definitely not sustainable.

We already have the ability to auto-generate an options schema from the plugin options. If we augmented the definitions of plugin options to include some documentation, we could potentially generate a more complete and automatically up-to-date documentation page for plugin options.

[michaelpj]

Related: #3156

[michaelpj]

I think this wouldn't be too hard. We already have some code that turns the plugin config into a vscode extension schema, we could write a very similar piece of code that turned it into e.g. a markdown table.