point errors related to nonlocals and globals to the statement declaring them (closes #10189)

Include/symtable.h

@@ -39,6 +39,7 @@ typedef struct _symtable_entry {
     PyObject *ste_name;      /* string: name of current block */
     PyObject *ste_varnames;  /* list of function parameters */
     PyObject *ste_children;  /* list of child blocks */
+    PyObject *ste_directives;/* locations of global and nonlocal statements */
     _Py_block_ty ste_type;   /* module, class, or function */
     int ste_unoptimized;     /* false if namespace is optimized */
     int ste_nested;      /* true if block is nested */