Binary serialization API about RID is incorrect

**Your Godot version:**
4.4 latest

**Issue description:**
The document states that RID doesn't support serialization, but in fact RID can be serialized and deserialized (as int64) using `var_to_bytes` and `bytes_to_var`, even if the corresponding resource can't be serialized and may not be valid. For example `var_to_bytes(rid_from_int64(13))` returns [23,0,0,0,13,0,0,0,0,0,0,0]

serialize:
https://github.com/godotengine/godot/blob/36d90c73a843afa2807a0b8dcbfbf52bdb8a759c/core/io/marshalls.cpp#L1732-L1739

deserialize:
https://github.com/godotengine/godot/blob/36d90c73a843afa2807a0b8dcbfbf52bdb8a759c/core/io/marshalls.cpp#L689-L697

**URL to the documentation page:**
https://docs.godotengine.org/en/latest/tutorials/io/binary_serialization_api.html#rid-unsupported