Issue #21818: Fixed references to classes that have names matching with module
names.
diff --git a/Doc/library/mutex.rst b/Doc/library/mutex.rst
index 57c3971..eb783f3 100644
--- a/Doc/library/mutex.rst
+++ b/Doc/library/mutex.rst
@@ -40,7 +40,7 @@
 Mutex Objects
 -------------
 
-:class:`mutex` objects have following methods:
+:class:`~mutex.mutex` objects have following methods:
 
 
 .. method:: mutex.test()