FIX-modin-project#1806: Updated headers for test files

Signed-off-by: Todd Yu <[email protected]>

modin/pandas/test/dataframe/test_multiindex.py

@@ -9,7 +9,7 @@
 # Unless required by applicable law or agreed to in writing, software distributed under
 # the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
 # ANY KIND, either express or implied. See the License for the specific language
-# governing permissions and limitations under the License.import pytest
+# governing permissions and limitations under the License.
 
 import pytest
 import numpy as np