Typo + Add Warning class for deprecation.

Also set the stack level to 2, to get the warning where the context
manager is constructed, if used.

IPython/core/completer.py

@@ -1,7 +1,7 b''
 # encoding: utf-8
 """Word completion for IPython.
 
-This module stared as fork of the rlcompleter module in the Python standard
+This module started as fork of the rlcompleter module in the Python standard
 library.  The original enhancements made to rlcompleter have been sent
 upstream and were accepted as of Python 2.3,
 

IPython/utils/contexts.py

@@ -67,7 +67,8 b' class NoOpContext(object):'
     Context manager that does nothing."""
 
     def __init__(self):
-        warnings.warn("""NoOpContext is deprecated since IPython 5.0 """)
+        warnings.warn("""NoOpContext is deprecated since IPython 5.0 """,
+                                            DeprecationWarning, stacklevel=2)
 
     def __enter__(self): pass
     def __exit__(self, type, value, traceback): pass