Fix broken cref

Author: mikekistler

src/Http/Routing/src/Builder/RoutingEndpointConventionBuilderExtensions.cs

@@ -4,6 +4,7 @@
 using Microsoft.AspNetCore.Http.Metadata;
 using Microsoft.AspNetCore.Routing;
 using Microsoft.AspNetCore.WebUtilities;
+using Microsoft.AspNetCore.Mvc.ApiExplorer;
 
 namespace Microsoft.AspNetCore.Builder;
 

src/Http/Routing/src/Microsoft.AspNetCore.Routing.csproj

@@ -46,6 +46,7 @@
     <Reference Include="Microsoft.AspNetCore.Http.Extensions" />
     <Reference Include="Microsoft.AspNetCore.Http.Features" />
     <Reference Include="Microsoft.AspNetCore.Http.Abstractions" />
+    <Reference Include="Microsoft.AspNetCore.Mvc.ApiExplorer" />
     <Reference Include="Microsoft.AspNetCore.Routing.Abstractions" />
     <Reference Include="Microsoft.Extensions.Diagnostics" />
     <Reference Include="Microsoft.Extensions.Features" />