Misc. typo fixes

Found via `codespell -q 3`

IPython/core/compilerop.py

@@ -40,7 +40,7 b' import time'
 # Constants
 #-----------------------------------------------------------------------------
 
-# Roughtly equal to PyCF_MASK | PyCF_MASK_OBSOLETE as defined in pythonrun.h,
+# Roughly equal to PyCF_MASK | PyCF_MASK_OBSOLETE as defined in pythonrun.h,
 # this is used as a bitmask to extract future-related code flags.
 PyCF_MASK = functools.reduce(operator.or_,
                              (getattr(__future__, fname).compiler_flag

IPython/core/hooks.py

@@ -174,7 +174,7 b' class CommandChainDispatcher:'
 def shutdown_hook(self):
     """ default shutdown hook
 
-    Typically, shotdown hooks should raise TryNext so all shutdown ops are done
+    Typically, shutdown hooks should raise TryNext so all shutdown ops are done
     """
 
     #print "default shutdown hook ok" # dbg

IPython/core/prefilter.py

@@ -82,7 +82,7 b' class PrefilterManager(Configurable):'
     prefilter consumes lines of input and produces transformed lines of
     input.
 
-    The iplementation consists of two phases:
+    The implementation consists of two phases:
 
     1. Transformers
     2. Checkers and handlers

IPython/lib/pretty.py

@@ -765,7 +765,7 b' if _env_type is not dict:'
 
 try:
     # In PyPy, types.DictProxyType is dict, setting the dictproxy printer
-    # using dict.setdefault avoids overwritting the dict printer
+    # using dict.setdefault avoids overwriting the dict printer
     _type_pprinters.setdefault(types.DictProxyType,
                                _dict_pprinter_factory('dict_proxy({', '})'))
     _type_pprinters[types.ClassType] = _type_pprint

IPython/testing/plugin/test_refs.py

@@ -21,7 +21,7 b' def doctest_run():'
     """
     
 def doctest_runvars():
-    """Test that variables defined in scripts get loaded correcly via %run.
+    """Test that variables defined in scripts get loaded correclty via %run.
 
     In [13]: run simplevars.py
     x is: 1