gh-159739: Track group records for cyclic garbage collection (#159778)

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>

Misc/NEWS.d/next/Library/2026-10-19-20-38-17.gh-issue-159739.bc65da.rst

@@ -0,0 +1,2 @@
+Allow cyclic garbage collection to reclaim group records returned by
+:mod:`grp`.

Modules/grpmodule.c

@@ -111,6 +111,7 @@ mkgrent(PyObject *module, struct group *p)
         return NULL;
     }
 
+    PyObject_GC_Track(v);
     return v;
 }