Fix a tiny typo in multi-parameter-symbols.py
Replaced "option" by "argument"
@@ -3,7 +3,7 @@ Multi-parameter symbols
-------------------------
The :meth:`pygmt.Figure.plot` method can plot individual multi-parameter symbols by passing
-the corresponding shortcuts listed below to the ``style`` option. Additionally, we must define
+the corresponding shortcuts listed below to the ``style`` argument. Additionally, we must define
the required parameters in a 2d list or numpy array (``[[parameters]]`` for a single symbol
or ``[[parameters_1],[parameters_2],[parameters_i]]`` for several ones) or use an
appropriately formatted input file and pass it to ``data``.
