Trivial spelling repair on new cyclic garbage text.
diff --git a/Doc/ext/extending.tex b/Doc/ext/extending.tex
index 7fe07b8..a0a0440 100644
--- a/Doc/ext/extending.tex
+++ b/Doc/ext/extending.tex
@@ -1238,9 +1238,9 @@
or indirect circular references; these are the weakness of garbage
collection implemented using only reference counting. Reference
cycles consist of objects which contain (possibly indirect) references
-themselves so that each object in the cycle has a reference count
+to themselves, so that each object in the cycle has a reference count
which is non-zero. Typical reference counting implementations are not
-able to reclaim the memory beloning to any objects in a reference
+able to reclaim the memory belonging to any objects in a reference
cycle, or referenced from the objects in the cycle, even though there
are no further references to the cycle itself.