remove duplicate line from docstring (aws#59)

Co-authored-by: Shunjia Ding <[email protected]>

Author: alex

src/stepfunctions/steps/states.py

@@ -538,7 +538,6 @@ def __init__(self, state_id, **kwargs):
             input_path (str, optional): Path applied to the state’s raw input to select some or all of it; that selection is used by the state. (default: '$')
             parameters (dict, optional): The value of this field becomes the effective input for the state.
             result_path (str, optional): Path specifying the raw input’s combination with or replacement by the state’s result. (default: '$')
-            result_path (str, optional): Path specifying the raw input’s combination with or replacement by the state’s result. (default: '$')
             output_path (str, optional): Path applied to the state’s output after the application of `result_path`, producing the effective output which serves as the raw input for the next state. (default: '$')
         """
         super(Map, self).__init__(state_id, 'Map', **kwargs)