add Tact language

[novusnota]

About

Tact is a smart contract programming language for TON Blockchain.

It is supported in tokei and on GitHub:

message(1) Ping {}
message(2) Pong {}
message(3) Hello {}

contract HelloWorld {
    receive(_: Ping) {
        reply(Pong {}.toCell());
    }

    receive(_: Hello) {
        reply(Hello {}.toCell());
    }

    receive() {
        cashback(sender());
    }
}

inline fun reply(msgBody: Cell) {
    message(MessageParameters {
        to: sender(),
        value: 0,
        mode: SendRemainingValue | SendIgnoreErrors,
        body: msgBody,
    });
}

Changes made

• Added an entry in languages.json and ran go generate
• Added an example to examples/ folder and an entry to LANGUAGES.md
• Run all tests via test-all.sh

Hope everything is correct here :)

[boyter]

Thanks so much for this! Will make the next release.