Docs about how to rebuild Mono runtime are outdated

[akoeplinger]

Android framework version

Other

Affected platform version

.NET

Description

See https://github.com/dotnet/android/blob/main/Documentation/building/unix/instructions.md#how-do-i-rebuild-the-mono-runtime-and-native-binaries, it talks about legacy Mono. A lot of the other steps in the doc look outdated too

Steps to Reproduce

Did you find any workaround?

Relevant log output