Fix PEP-8 issues in internals.rst (pandas-dev#23903)

Signed-off-by: Fabian Haase <[email protected]>

Author: FHaase

doc/source/internals.rst

@@ -6,9 +6,10 @@
    :suppress:
 
    import numpy as np
+   import pandas as pd
+
    np.random.seed(123456)
    np.set_printoptions(precision=4, suppress=True)
-   import pandas as pd
    pd.options.display.max_rows = 15
 
 *********
@@ -77,7 +78,8 @@ integer **labels**, and the level **names**:
 
 .. ipython:: python
 
-   index = pd.MultiIndex.from_product([range(3), ['one', 'two']], names=['first', 'second'])
+   index = pd.MultiIndex.from_product([range(3), ['one', 'two']],
+                                      names=['first', 'second'])
    index
    index.levels
    index.labels