Upgrade to HLS 2.1.0.0

[tfausak]

https://discourse.haskell.org/t/ann-haskell-language-server-2-1-0-0-is-now-available/7272?u=taylorfausak

[codygman]

@acilearning/backend This should make reformatting work better because it's more compliant to the LSP spec:

Fix code edits in lsp spec compliant editors like helix. (#3643 3)

tldr; They weren't sending an updated version after modifying the document before and now they are, so less things should break.