Change a function to remove C++23 dependancy

README.md

@@ -12,7 +12,7 @@ The end goal is to emit bytecode. The bytecode format is not decided yet.
 All you need is:
 
 - CMake
-- An appropriate C++ compiler
+- A modern C++ compiler
 - The [Catch2](https://github.com/catchorg/Catch2) library v3 or higher installed on your system
 
 Once you have these, you can build with:

src/parse.cpp

@@ -11,8 +11,9 @@ using namespace std;
 
 Parser::Parser(Lexer l) : ts(l.collect()) {}
 
-void Parser::feed(Lexer l) {
-    ts.append_range(l.collect());
+void Parser::feed(Lexer lexer) {
+    auto l = lexer.collect();
+    ts.insert(ts.end(), l.begin(), l.end());
 }
 
 Token Parser::get_token() {