[otlp] Add comments capturing details about SYSLIB1100 & SYSLIB1101 suppressions in project (#5523)

Author: CodeBlanch

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/OpenTelemetry.Exporter.OpenTelemetryProtocol.csproj

@@ -9,7 +9,14 @@
     <Nullable>disable</Nullable>
     <DefineConstants>BUILDING_INTERNAL_PERSISTENT_STORAGE;$(DefineConstants)</DefineConstants>
     <EnableConfigurationBindingGenerator>true</EnableConfigurationBindingGenerator>
-    <!-- SYSLIB1100;SYSLIB1101 - Configuration.Binder: can't create instance and unsupported type -->
+
+    <!-- Note: SYSLIB1100;SYSLIB1101 - Configuration.Binder: Can't create
+    instance and unsupported type are being emitted by config source generator
+    processing OtlpExporterBuilderOptions. It would be preferable to suppress
+    this at the call site but there is a bug. This could possibly be cleaned up
+    in the future (hopefully .NET 9) see:
+    https://github.com/open-telemetry/opentelemetry-dotnet/pull/5520#discussion_r1556221048
+    and https://github.com/dotnet/runtime/issues/92509 -->
     <NoWarn>$(NoWarn);SYSLIB1100;SYSLIB1101</NoWarn>
   </PropertyGroup>