Clarify HTTP/gRPC exporter examples (#3492)

Signed-off-by: Yuri Shkuro <github@ysh.us>

example/otel-collector/main.go

@@ -57,10 +57,14 @@ func initProvider() (func(context.Context) error, error) {
 	// microk8s), it should be accessible through the NodePort service at the
 	// `localhost:30080` endpoint. Otherwise, replace `localhost` with the
 	// endpoint of your cluster. If you run the app inside k8s, then you can
-	// probably connect directly to the service through dns
+	// probably connect directly to the service through dns.
 	ctx, cancel := context.WithTimeout(ctx, time.Second)
 	defer cancel()
-	conn, err := grpc.DialContext(ctx, "localhost:30080", grpc.WithTransportCredentials(insecure.NewCredentials()), grpc.WithBlock())
+	conn, err := grpc.DialContext(ctx, "localhost:30080",
+		// Note the use of insecure transport here. TLS is recommended in production.
+		grpc.WithTransportCredentials(insecure.NewCredentials()),
+		grpc.WithBlock(),
+	)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create gRPC connection to collector: %w", err)
 	}

exporters/otlp/otlptrace/README.md

@@ -12,8 +12,8 @@ go get -u go.opentelemetry.io/otel/exporters/otlp/otlptrace
 
 ## Examples
 
-- [Exporter setup and examples](./otlptracehttp/example_test.go)
-- [Full example sending telemetry to a local collector](../../../example/otel-collector)
+- [HTTP Exporter setup and examples](./otlptracehttp/example_test.go)
+- [Full example of gRPC Exporter sending telemetry to a local collector](../../../example/otel-collector)
 
 ## [`otlptrace`](https://pkg.go.dev/go.opentelemetry.io/otel/exporters/otlp/otlptrace)