Remove mention of deprecated xreadlines method.

Doc/lib/libgzip.tex

@@ -21,8 +21,8 @@ The module defines the following items:
 \begin{classdesc}{GzipFile}{\optional{filename\optional{, mode\optional{,
                             compresslevel\optional{, fileobj}}}}}
 Constructor for the \class{GzipFile} class, which simulates most of
-the methods of a file object, with the exception of the \method{readinto()},
-\method{truncate()}, and \method{xreadlines()} methods.  At least one of
+the methods of a file object, with the exception of the \method{readinto()}
+and \method{truncate()} methods.  At least one of
 \var{fileobj} and \var{filename} must be given a non-trivial value.
 
 The new class instance is based on \var{fileobj}, which can be a

Lib/gzip.py

@@ -37,7 +37,7 @@ def open(filename, mode="rb", compresslevel=9):
 
 class GzipFile:
     """The GzipFile class simulates most of the methods of a file object with
-    the exception of the readinto(), truncate(), and xreadlines() methods.
+    the exception of the readinto() and truncate() methods.
 
     """