Fix python extension import (#1000)

diff --git a/bindings/python/google_benchmark/__init__.py b/bindings/python/google_benchmark/__init__.py
index 378f030..c3a93bf 100644
--- a/bindings/python/google_benchmark/__init__.py
+++ b/bindings/python/google_benchmark/__init__.py
@@ -14,7 +14,7 @@
 """Python benchmarking utilities.
 
 Example usage:
-  import benchmark
+  import google_benchmark as benchmark
 
   @benchmark.register
   def my_benchmark(state):
@@ -28,7 +28,7 @@
 """
 
 from absl import app
-from benchmark import _benchmark
+from google_benchmark import _benchmark
 
 __all__ = [
     "register",