Fix typos; enhance comments on patch for SF #1462485.

--This line, and those below, will be ignored--

M    contextlib.py

Lib/contextlib.py

@@ -32,8 +32,9 @@ class GeneratorContextManager(object):
                 self.gen.throw(type, value, traceback)
                 raise RuntimeError("generator didn't stop after throw()")
             except StopIteration:
-                # Supress the exception unless it's the same exception the
-                # was passed to throw().
+                # Suppress the exception *unless* it's the same exception that
+                # was passed to throw().  This prevents a StopIteration
+                # raised inside the "with" statement from being suppressed
                 return sys.exc_info()[1] is not value
             except:
                 # only re-raise if it's *not* the exception that was