LibCpp: Use lex_iterable() where applicable

Author: https://github.com/itamar8910
Commit: f91974677c
Pull-request: https://github.com/SerenityOS/serenity/pull/9528
Reviewed-by: https://github.com/alimpfard

Userland/Utilities/cpp-lexer.cpp

@@ -24,9 +24,7 @@ int main(int argc, char** argv)
     StringView content_view(content);
 
     Cpp::Lexer lexer(content);
-    auto tokens = lexer.lex();
-
-    for (auto& token : tokens) {
+    lexer.lex_iterable([](auto token) {
         outln("{}", token.to_string());
-    }
+    });
 }