Add support for the Rell language

[CommanderTvis]

This PR adds syntax highlighting support for Rell, a blockchain programming language developed for the Chromia platform.

What is Rell?

Rell is a type-safe, relational programming language designed specifically for decentralized application (dapp) development on blockchain platforms. It combines relational database concepts with modern programming language features, allowing developers to describe data models, queries, and procedural code in a concise and expressive way. Database queries in Rell are compiled to SQL. The language is designed to be familiar to developers who know languages like JavaScript and Kotlin.

References

• Rell Documentation: https://docs.chromia.com/rell/rell-intro
• Rell Grammar: https://gitlab.com/chromaway/rell/-/blob/dev/rell-base/src/main/kotlin/net/postchain/rell/base/compiler/parser/grammar.kt
• Rell Lexer in Pygments: https://github.com/pygments/pygments/blob/master/pygments/lexers/rell.py

Affiliation Notice

As of November 7, 2025, I (Iaroslav Postovalov) develop Rell's interpreter professionally.

[alexj136]

Looks good to me.