fixed some const char*

src/lisp_object.cpp

@@ -1,4 +1,4 @@
-proc create_source_code_location(char* file, int line, int col) -> Source_Code_Location* {
+proc create_source_code_location(const char* file, int line, int col) -> Source_Code_Location* {
     if (!file)
         return nullptr;
 
@@ -9,7 +9,7 @@ proc create_source_code_location(char* file, int line, int col) -> Source_Code_L
     return ret;
 }
 
-proc Lisp_Object_Type_to_string(Lisp_Object_Type type) -> char* {
+proc Lisp_Object_Type_to_string(Lisp_Object_Type type) -> const char* {
     switch (type) {
     case(Lisp_Object_Type::Nil):       return "nil";
     case(Lisp_Object_Type::T):         return "t";