correct docstring

Author: charlesdong1991

pandas/core/internals/managers.py

@@ -1967,7 +1967,7 @@ def items_overlap_with_suffix(left, lsuffix, right, rsuffix):
         def renamer(x, suffix):
             """Rename the left and right indices.
 
-            If there is overlap, and suffix is not None or False, add
+            If there is overlap, and suffix is not None, add
             suffix, otherwise, leave it as-is.
 
             Parameters