[docs] document new config values

[jrushlow]

• depends on [make:crud|voter] generate classes with final keyword #1539

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• adds the ability to generate / preview our single page doc locally (https://symfony.com/bundles/SymfonyMakerBundle/current/index.html)

Yup - totally stole the code from https://github.com/symfony/symfony-docs/tree/7.1/_build to preview the build

Open to ideas on how we can preview the docs that ultimately get published on symfony.com without doing the whole "make change -> merge PR" rinse and repeat cycle...

[javiereguiluz]

I think this is correct. Thanks Jesse!

If we assume that the doc of this bundle will always be a single page (which I think it's safe to assume) then you could simplify some things if you want:

• You could remove the disable-cache option because when having 1 doc page, it doesn't make any noticeable difference
• All the logic related to this --> "fix assets URLs to make them absolute (otherwise, they don't work in subdirectories)" could be removed because you don't have images and, if you include images in the future, you won't have subdirectories for contents because all the docs are in a single page

A final comment: something very useful for us is to run a RST linter to docs. It detects so many issues! We use DOCtor-RST (created by @OskarStark and actively developed by folks like @alamirault). We use it like this:

https://github.com/symfony/symfony-docs/blob/9bfc9fad274711f88b77364b7d36a7db86c79f7f/.github/workflows/ci.yaml#L53-L78