docs: fix simple typo, intsead -> instead (JelteF#316)

There is a small typo in pylatex/base_classes/command.py.

Should read `instead` rather than `intsead`.

Author: timgates42

pylatex/base_classes/command.py

@@ -379,7 +379,7 @@ def dumps(self):
 
 
 class SpecialArguments(Arguments):
-    """A class that separates arguments with ',' intsead of '}{'."""
+    """A class that separates arguments with ',' instead of '}{'."""
 
     def dumps(self):
         """Represent the parameters as a string in LaTeX syntax.