Add example test to SDK for doc (#1100)

sdk/example_test.go

@@ -0,0 +1,18 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package sdk
+
+import "context"
+
+func ExampleGetTracerProvider() {
+	// Get a Tracer from an auto-instrumented TracerProvider so all spans
+	// created will be passed to the auto-instrumentation telemetry pipeline.
+	tracer := GetTracerProvider().Tracer("my.pkg/name")
+
+	// The tracer is used normally to create spans to encapsulate work.
+	_, span := tracer.Start(context.Background(), "do.work")
+	defer span.End()
+
+	// Do work ...
+}