Add comment to gRPC template tests SkipOnAlpine attribute (#46517)

Author: JamesNK

src/ProjectTemplates/test/Templates.Tests/GrpcTemplateTest.cs

@@ -36,31 +36,31 @@ public ITestOutputHelper Output
 
     [ConditionalFact]
     [SkipOnHelix("Not supported queues", Queues = "windows.11.arm64.open;" + HelixConstants.Windows10Arm64 + HelixConstants.DebianArm64)]
-    [SkipOnAlpine("https://github.com/grpc/grpc/issues/18338")]
+    [SkipOnAlpine("https://github.com/grpc/grpc/issues/18338")] // protoc doesn't support Alpine. Note that the issue was closed with a workaround which isn't applied to our OS image.
     public async Task GrpcTemplate()
     {
         await GrpcTemplateCore();
     }
 
     [ConditionalFact(Skip = "Unskip when there are no more build or publish warnings for native AOT.")]
     [SkipOnHelix("Not supported queues", Queues = "windows.11.arm64.open;" + HelixConstants.Windows10Arm64 + HelixConstants.DebianArm64)]
-    [SkipOnAlpine("https://github.com/grpc/grpc/issues/18338")]
+    [SkipOnAlpine("https://github.com/grpc/grpc/issues/18338")] // protoc doesn't support Alpine. Note that the issue was closed with a workaround which isn't applied to our OS image.
     public async Task GrpcTemplateNativeAot()
     {
         await GrpcTemplateCore(args: new[] { ArgConstants.PublishNativeAot });
     }
 
     [ConditionalFact]
     [SkipOnHelix("Not supported queues", Queues = "windows.11.arm64.open;" + HelixConstants.Windows10Arm64 + HelixConstants.DebianArm64)]
-    [SkipOnAlpine("https://github.com/grpc/grpc/issues/18338")]
+    [SkipOnAlpine("https://github.com/grpc/grpc/issues/18338")] // protoc doesn't support Alpine. Note that the issue was closed with a workaround which isn't applied to our OS image.
     public async Task GrpcTemplateProgramMain()
     {
         await GrpcTemplateCore(args: new[] { ArgConstants.UseProgramMain });
     }
 
     [ConditionalFact(Skip = "Unskip when there are no more build or publish warnings for native AOT.")]
     [SkipOnHelix("Not supported queues", Queues = "windows.11.arm64.open;" + HelixConstants.Windows10Arm64 + HelixConstants.DebianArm64)]
-    [SkipOnAlpine("https://github.com/grpc/grpc/issues/18338")]
+    [SkipOnAlpine("https://github.com/grpc/grpc/issues/18338")] // protoc doesn't support Alpine. Note that the issue was closed with a workaround which isn't applied to our OS image.
     public async Task GrpcTemplateProgramMainNativeAot()
     {
         await GrpcTemplateCore(args: new[] { ArgConstants.UseProgramMain, ArgConstants.PublishNativeAot });