Keep documentation on symbols in sync with the README's

[dirkdev98]

We manually copy and paste the documentation changes from, for example, the pull-through-cache to the README. It might be nice to use TypeDoc for this. However, not really a fan of the default output, or the output of typedoc-plugin-markdown.

Like Ion we can probably use TypeDoc's parsers to massage the available info in a different output format. This also requires some rules around docs;

• Which symbols are included in the generated docs and in what order?
• Do we want to generate the whole README, or just the API sections?
• What rules do we need to enforce on TS doc blocks?
• ...

We probably should wait for at least one package before we start working on this, so we don't design this purely for the pull-through-cache.