Mention in the fnmatch docs that meta-characters in translate cannot be quoted.

Closes issue 9358. Thanks to Brian Brazil for the patch.
diff --git a/Doc/library/fnmatch.rst b/Doc/library/fnmatch.rst
index ec78ed2..49073c5 100644
--- a/Doc/library/fnmatch.rst
+++ b/Doc/library/fnmatch.rst
@@ -70,6 +70,8 @@
 
    Return the shell-style *pattern* converted to a regular expression.
 
+   Be aware there is no way to quote meta-characters.
+
    Example:
 
       >>> import fnmatch, re