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/netrc.rst b/Doc/library/netrc.rst
index e6cc648..91990df 100644
--- a/Doc/library/netrc.rst
+++ b/Doc/library/netrc.rst
@@ -66,9 +66,8 @@
 
 .. note::
 
-   Passwords are limited to a subset of the ASCII character set. Versions of
-   this module prior to 2.3 were extremely limited.  Starting with 2.3, all
-   ASCII punctuation is allowed in passwords.  However, note that whitespace and
+   Passwords are limited to a subset of the ASCII character set.  All ASCII
+   punctuation is allowed in passwords, however, note that whitespace and
    non-printable characters are not allowed in passwords.  This is a limitation
    of the way the .netrc file is parsed and may be removed in the future.