How to customize help following change to HelpBuilder visibility

[barrygiles]

Sorry if this is obvious, but I was wondering what the suggested migration path would look like for customized help layouts, now that the HelpBuilder is internal: 8363e58

dotnet/runtime#116065 as an example extends the help layout, but I'm wondering about customizing the main layout.

I've looked at the tests, e.g. https://github.com/dotnet/command-line-api/blob/8363e585244577511e5178bc441fbec7cf9c6053/src/System.CommandLine.Tests/Help/HelpBuilderTests.Customization.cs, but these seem to have access to the internal HelpBuilder, so I don't think are much use as a guide.

So I'm a bit confused, but probably missing something obvious.

[calacayir]

I am concerned with this change as well, we depend on public HelpBuilder classes/methods to customize it in this project:
https://github.com/dotmake-build/command-line
But now we cannot update beyond daily build of 2.0.0-beta5.25302.104 of System.CommandLine for this reason.