- Prior to this imported `@page` directives would flow through the Razor system without error. This resulted in inconsistent behavior between MVC and Razor. Now, imported `@page` directives result in diagnostics on the page directive node.
- Added two tests to verify that we still treat views with imported page directives as Razor pages BUT we also log a diagnostic on the page directive node.
- Renamed the `ViewComponentDiagnosticFactory` class to `RazorExtensionsDiagnosticFactory` so it can be used for more than just view component diagnostics. This way we can ensure that our diagnostics don't end up overlapping.
#1503
d36838ed88