Remove many "versionchanged" items that didn't use the official markup,
but just some text embedded in the docs.

Also remove paragraph about implicit relative imports from tutorial.
diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
index f66899c..0929f0e 100644
--- a/Doc/library/sys.rst
+++ b/Doc/library/sys.rst
@@ -152,21 +152,18 @@
 
    .. warning::
 
-      Assigning the *traceback* return value to a local variable in a function that is
-      handling an exception will cause a circular reference.  This will prevent
-      anything referenced by a local variable in the same function or by the traceback
-      from being garbage collected.  Since most functions don't need access to the
-      traceback, the best solution is to use something like ``exctype, value =
-      sys.exc_info()[:2]`` to extract only the exception type and value.  If you do
-      need the traceback, make sure to delete it after use (best done with a
-      :keyword:`try` ... :keyword:`finally` statement) or to call :func:`exc_info` in
-      a function that does not itself handle an exception.
+      Assigning the *traceback* return value to a local variable in a function
+      that is handling an exception will cause a circular reference.  Since most
+      functions don't need access to the traceback, the best solution is to use
+      something like ``exctype, value = sys.exc_info()[:2]`` to extract only the
+      exception type and value.  If you do need the traceback, make sure to
+      delete it after use (best done with a :keyword:`try`
+      ... :keyword:`finally` statement) or to call :func:`exc_info` in a
+      function that does not itself handle an exception.
 
-   .. note::
-
-      Beginning with Python 2.2, such cycles are automatically reclaimed when garbage
-      collection is enabled and they become unreachable, but it remains more efficient
-      to avoid creating cycles.
+      Such cycles are normally automatically reclaimed when garbage collection
+      is enabled and they become unreachable, but it remains more efficient to
+      avoid creating cycles.
 
 
 .. data:: exec_prefix