Update frame.py (pandas-dev#14724)

typo "explicitly"

Author: sdimi

pandas/core/frame.py

@@ -3233,7 +3233,7 @@ def trans(v):
                 # try to be helpful
                 if isinstance(self.columns, MultiIndex):
                     raise ValueError('Cannot sort by column %s in a '
-                                     'multi-index you need to explicity '
+                                     'multi-index you need to explicitly '
                                      'provide all the levels' % str(by))
 
                 raise ValueError('Cannot sort by duplicate column %s' %