gh-140550: Use a bool for the Py_mod_gil value (GH-141519)

This needs a single bit, but was stored as a void* in the module
struct. This didn't matter due to packing, but now that there's
another bool in the struct, we can save a bit of memory by
making md_gil a bool.

Variables that changed type are renamed, to detect conflicts.

Include/internal/pycore_moduleobject.h

@@ -30,7 +30,7 @@ typedef struct {
     PyObject *md_name;
     bool md_token_is_def;  /* if true, `md_token` is the PyModuleDef */
 #ifdef Py_GIL_DISABLED
-    void *md_gil;
+    bool md_requires_gil;
 #endif
     Py_ssize_t md_state_size;
     traverseproc md_state_traverse;