Guide users to enable `libReplacement: true`

[uhyo]

According to microsoft/TypeScript#60829 we need to guide users to enable libReplacement: true so that better-typescript-lib can work. In the future (tentatively said to >= TS 6.0) the lib replacement behavior won't be the default 🥲

This should be added to README when we release a new version which officially supports the version of TypeScript with that option.