py/scope: Name and use id_kind_type_t.

The function scope_find_or_add_id used to take a scope_kind_t enum and
save it in an uint8_t. Saving an enum in a uint8_t is fine, but
everywhere this function is called it is not actually given a
scope_kind_t but an anonymous enum instead. Let's give this enum a name
and use that as the argument type.

This doesn't change the generated code, but is a C type mismatch that
unfortunately doesn't show up unless you enable -Wenum-conversion.

py/scope.c

@@ -72,7 +72,7 @@ void scope_free(scope_t *scope) {
     m_del(scope_t, scope, 1);
 }
 
-id_info_t *scope_find_or_add_id(scope_t *scope, qstr qst, scope_kind_t kind) {
+id_info_t *scope_find_or_add_id(scope_t *scope, qstr qst, id_info_kind_t kind) {
     id_info_t *id_info = scope_find(scope, qst);
     if (id_info != NULL) {
         return id_info;

py/scope.h

@@ -29,14 +29,14 @@
 #include "py/parse.h"
 #include "py/emitglue.h"
 
-enum {
+typedef enum {
     ID_INFO_KIND_UNDECIDED,
     ID_INFO_KIND_GLOBAL_IMPLICIT,
     ID_INFO_KIND_GLOBAL_EXPLICIT,
     ID_INFO_KIND_LOCAL, // in a function f, written and only referenced by f
     ID_INFO_KIND_CELL,  // in a function f, read/written by children of f
     ID_INFO_KIND_FREE,  // in a function f, belongs to the parent of f
-};
+} id_info_kind_t;
 
 enum {
     ID_FLAG_IS_PARAM = 0x01,
@@ -92,7 +92,7 @@ typedef struct _scope_t {
 
 scope_t *scope_new(scope_kind_t kind, mp_parse_node_t pn, qstr source_file, mp_uint_t emit_options);
 void scope_free(scope_t *scope);
-id_info_t *scope_find_or_add_id(scope_t *scope, qstr qstr, scope_kind_t kind);
+id_info_t *scope_find_or_add_id(scope_t *scope, qstr qstr, id_info_kind_t kind);
 id_info_t *scope_find(scope_t *scope, qstr qstr);
 id_info_t *scope_find_global(scope_t *scope, qstr qstr);
 void scope_check_to_close_over(scope_t *scope, id_info_t *id);