fix typo in %load docstring

Since I was reading it for reference

IPython/core/magics/code.py

@@ -157,7 +157,7 b' class CodeMagics(Magics):'
     def loadpy(self, arg_s):
         """Alias of `%load`
 
-        `%loadpy` has gained some flexibility and droped the requirement of a `.py`
+        `%loadpy` has gained some flexibility and dropped the requirement of a `.py`
         extension. So it has been renamed simply into %load. You can look at
         `%load`'s docstring for more info.
         """