MQL Language Setup Support (instructions in doc)

[myisaak]

Not a feature, but enhancement of the supported list of languages.

To save time, one would appreciate clangd-based setup instructions for the MQL (MetaQuotes Language), a C++ variant used by MetaTrader5. Ideally, a setup working config snippet of languages.toml.

This repo provides the internal header files used in MQL for generic C++ compilation: https://github.com/mskelton/mql5/tree/main

This repo provides a working MQL editor integration: https://github.com/marketersuman/vim-mql5