Update encoding_and_decoding.py

kyu_3/rail_fence_cipher_encoding_and_decoding/encoding_and_decoding.py:10 in public function `get_rails`:
        D205: 1 blank line required between summary line and description (found 0)

        Multi-line docstrings consist of a summary line just like a one-line
        docstring, followed by a blank line, followed by a more elaborate
        description. The summary line may be used by automatic indexing tools;
        it is important that it fits on one line and is separated from the
        rest of the docstring by a blank line.

kyu_3/rail_fence_cipher_encoding_and_decoding/encoding_and_decoding.py

@@ -9,6 +9,7 @@
 def get_rails(string: str, n: int) -> list:
     """
     Create rails matrix.
+    
     :param string: str
     :param n: int, the number of rails
     :return: list, rails matrix