Say why the byte emitter takes no check_shared

runtime/flan_dev.c

@@ -369,6 +369,9 @@ void flan_dev_emit_str(const uint8_t *bytes, int64_t len) {
  * comparisons because the value is only known at run time: a chain over
  * ninety-odd bytes per rendered u8 would be the walk paying for its own
  * shape, and the table belongs in one place. */
+/* No [check_shared] here, deliberately: that guard checks [flan_f64_format]
+ * and [flan_escape_char] are the functions this file declares, and this uses
+ * neither — same as [put_u64] and [put_i64], which do not call it either. */
 void flan_dev_emit_u8_char(int64_t x) {
   const char *name = NULL;
   char        one[2];