Combine TK_TRUE and TK_FALSE into TK_BOOL

include/lexer/lexer.h

@@ -16,8 +16,7 @@ typedef enum {
   TK_L_BRACKET,
   TK_R_BRACKET,
   TK_NULL,
-  TK_TRUE,
-  TK_FALSE,
+  TK_BOOL,
   TK_STR_KEY,
   TK_STR_VAL,
   TK_INTEGER,
@@ -29,6 +28,7 @@ typedef union {
   i64 num_int;
   f64 num_frac;
   str_view_t string;
+  bool boolean;
 } token_value_t;
 
 typedef struct {