Implement String structure and update Location/Token to use it

v0/location.h

@@ -4,6 +4,8 @@
 #ifndef LOCATION_H
 #define LOCATION_H
 
+#include "string.h"
+
 #include <stddef.h>
 
 typedef struct {
@@ -11,16 +13,16 @@ typedef struct {
     char* filename;
 
 	/// @brief The entire line of text where the token was found.
-	char* line_text;
-
-	/// @brief The length of the `line_text` string.
-	size_t line_text_length;
+	String line_text;
 
 	/// @brief The line number where the token was found.
 	int line;
 
-	/// @brief The column number where the token was found.
-	int column;
+	/// @brief The starting column number where the token was found.
+	int column_start;
+
+	/// @brief The ending column number where the token was found.
+	int column_end;
 } Location;
 
 #endif