Typo: destuction --> destruction
Reported by Thomas Heller.
diff --git a/Doc/lib/libweakref.tex b/Doc/lib/libweakref.tex
index 4b3767e..73caf94 100644
--- a/Doc/lib/libweakref.tex
+++ b/Doc/lib/libweakref.tex
@@ -248,6 +248,6 @@
 
     PyObject_ClearWeakRefs((PyObject *) inst);
 
-    /* Proceed with object destuction normally. */
+    /* Proceed with object destruction normally. */
 }
 \end{verbatim}