Add amber-lang support

[lens0021]

Amber is

The Programming Language compiled to Bash. -- https://amber-lang.com/

But currently in their alpha stage.

[lens0021]

I tried the following configuration

[[grammar]]
name = "amber"
source = { git = "https://github.com/amber-lang/tree-sitter-amber", rev = "01bf07600a9ddc3a7c8a00d9e207dd35b156d93a" }

[[language]]
name = "amber"
scope = "source.ab"
file-types = ["ab"]
comment-token = ["//"]
indent = { tab-width = 4, unit = "    " }

And executed hx -g fetch amber and hx -g build but could not make the syntax highlighting to work. (I don't understand how Helix and tree sitter work!)

[lens0021]

https://docs.helix-editor.com/guides/adding_languages.html#queries are needed.

[lens0021]

https://github.com/amber-lang/amber-zed/tree/master/languages/amber contains scm files and the license is GPL3