Fix typo

Author: wtgodbe

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

@@ -32,7 +32,7 @@ Microsoft.AspNetCore.Routing.RouteCollection</Description>
     <Reference Include="Microsoft.AspNetCore.Http.Extensions" />
     <Reference Include="Microsoft.AspNetCore.Routing.Abstractions" />
 
-    <PackageReference Include="Microsoft.Extensions.HashCodeCombiner.Sources" Version="$MicrosoftExtensionsHashCodeCombinerSourcesPackageVersion)"/>
+    <PackageReference Include="Microsoft.Extensions.HashCodeCombiner.Sources" Version="$(MicrosoftExtensionsHashCodeCombinerSourcesPackageVersion)"/>
     <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="$(MicrosoftExtensionsLoggingAbstractionsPackageVersion)"/>
     <PackageReference Include="Microsoft.Extensions.ObjectPool" Version="$(MicrosoftExtensionsObjectPoolPackageVersion)"/>
     <PackageReference Include="Microsoft.Extensions.Options" Version="$(MicrosoftExtensionsOptionsPackageVersion)"/>