Support .surql SurrealDB files

[johnbchron]

It's SQL-like, and already has a full grammar: https://github.com/DariusCorvus/tree-sitter-surrealdb

This is the config I use with it, and it's well-formed AFAICT:

[[language]]
name = "surrealdb"
scope = "source.surrealdb"
file-types = [ "surql" ]
comment-tokens = "--"
indent = { tab-width = 2, unit = "  " }
grammar = "surrealdb"

[pascalkuthe]

A grammar needs a source descirption to be effective:

[[grammar]]
name = "rust"
source = { git = "https://github.com/tree-sitter/tree-sitter-rust", rev = "473634230435c18033384bebaa6d6a17c2523281" }

and (helix-specific) query definitions. One you have all that setup feel free to open a PR, no need to create an issue for something like this first.