More detailed sys.getdefaultencoding() documentation

Author: rruuaanng

Doc/library/sys.rst

@@ -771,8 +771,8 @@ always available. Unless explicitly noted otherwise, all variables are read-only
 
 .. function:: getdefaultencoding()
 
-   Return the name of the current default string encoding used by the Unicode
-   implementation.
+   Return ``'utf-8'``. This is the name of the default string encoding,
+   used in methods like str.encode.
 
 
 .. function:: getdlopenflags()