`a_hash_map.hpp` cannot be compiled in pedantic C++ mode

[hhyyrylainen]

Godot version

4.6.1

godot-cpp version

4.5 (60b5a41)

System information

Linux, gcc (GCC) 15.2.1 20260123 (Red Hat 15.2.1-7)

Issue description

Trying to compile any header that includes <godot_cpp/templates/a_hash_map.hpp> fails in pedantic C++ mode, with this error:

/home/hhyyrylainen/Projects/GodotCppTemplate/extension/../third_party/godot-cpp/include/godot_cpp/templates/a_hash_map.hpp:41:17: virhe: ISO C++ kieltää nimettömät structit [-Werror=pedantic]
   41 |                 {
      |                 ^

A rough translation into English of the error is that standard C++ forbids nameless structs.

Steps to reproduce

Try to compile the header <godot_cpp/templates/a_hash_map.hpp> with -Werror=pedantic using gcc

Minimal reproduction project

Nothing extra needed, just a header that is already in this repo.