Apply suggestion from @Copilot

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: matthiasgoergens

Modules/_collectionsmodule.c

@@ -78,7 +78,7 @@ struct dequeobject {
     PyObject_VAR_HEAD
     /* Vector of pointers to list elements.  list[0] is ob_item[0], etc. */
     PyObject **ob_item;
-    //  allocated needs to be a power of two
+    /* allocated needs to be a power of two */
     Py_ssize_t allocated;
     Py_ssize_t first_element;
     Py_ssize_t maxlen;