Adding snippets via post processing is no longer needed

[DoctorKrolic]

No idea why you didn't do this in https://github.com/dotnet/razor-tooling/pull/6012. Currently snippets are duplicating if display names are differen: Here for and foreach are snippets from language server, while for (...) and foreach (...) are added via post processing

In the same context in C# there are no duplicates like for & for (...) and so on:

Removing adding snippets via post processing will also fully fix https://github.com/dotnet/razor-tooling/issues/4299, because snippets from LSP all propper tooltip.