spanner: remove single-line comment cruft in package doc
@@ -22,8 +22,8 @@ and instances.
Note: This package is in alpha. Backwards-incompatible changes may occur
without notice.
-// See https://cloud.google.com/spanner/docs/getting-started/go/ for an introduction
-// to Cloud Spanner and additional help on using this API.
+See https://cloud.google.com/spanner/docs/getting-started/go/ for an introduction
+to Cloud Spanner and additional help on using this API.
Creating a Client
