fix dead link (#558)

(cherry picked from commit 48aad91)

Author: rustagir

source/usage-examples/insertMany.txt

@@ -55,7 +55,7 @@ corresponding code.
          :dedent:
 
       For a fully runnable example of the ``InsertManyAsync()`` operation, see the
-      `InsertManyAsync code sample <{+example+}/insert-many/InsertManyAysnc.cs>`__.
+      `InsertManyAsync code sample <{+example+}/insert-many/InsertManyAsync.cs>`__.
 
 Expected Result
 ~~~~~~~~~~~~~~~