refactor!: rename list to alternation

[amaanq]

Problem

In tree-sitter's query syntax, the construct described as a list in the current grammar is actually known as an alternation - see https://tree-sitter.github.io/tree-sitter/using-parsers#alternations

It would be better to rename this node to alternation, since it correctly captures what this node actually means in terms of the query syntax itself

Solution

Rename the node to alternation

[clason]

Note: this will break https://github.com/neovim/neovim/blob/2c6b6358722b2df9160c3739b0cea07e8779513f/runtime/lua/vim/treesitter/_query_linter.lua#L66-L78

Let me think whether it's possible to handle that gracefully -- right now, I don't see a way, in which case I don't think the more appropriate name is worth it.