When the Html language server returns results in the Go To Definition endpoint in Cohosting, the Uris it returns need to be checked and potentially remapped from __virtual.html Uris back to the .razor/.cshtml Uris they originated from.

This code:
https://github.com/dotnet/razor/blob/main/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/LanguageClient/Cohost/CohostGoToDefinitionEndpoint.cs#L116

Needs to do a little more of this:
https://github.com/dotnet/razor/blob/main/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Definition/DefinitionEndpoint.cs#L101