a couple of more stray XDG / .config references

IPython/core/usage.py

@@ -45,10 +45,9 b' Usage'
 
     This file is typically installed in the `IPYTHONDIR` directory, and there
     is a separate configuration directory for each profile. The default profile
-    directory will be located in $IPYTHONDIR/profile_default. For Linux users,
-    IPYTHONDIR defaults to `$HOME/.config/ipython`, and for other Unix systems
-    to `$HOME/.ipython`.  For Windows users, $HOME resolves to C:\\Documents
-    and Settings\\YourUserName in most instances.
+    directory will be located in $IPYTHONDIR/profile_default. IPYTHONDIR
+    defaults to to `$HOME/.ipython`.  For Windows users, $HOME resolves to
+    C:\\Documents and Settings\\YourUserName in most instances.
 
     To initialize a profile with the default configuration file, do::
 

docs/source/config/old.rst

@@ -12,8 +12,7 b' Outdated configuration information that might still be useful'
 This section will help you set various things in your environment for
 your IPython sessions to be as efficient as possible. All of IPython's
 configuration information, along with several example files, is stored
-in a directory named by default $HOME/.config/ipython if $HOME/.config 
-exists (Linux), or $HOME/.ipython as a secondary default. You can change this by
+in a directory named by default $HOME/.ipython. You can change this by
 defining the environment variable IPYTHONDIR, or at runtime with the
 command line option -ipythondir.