Helix's `lsp-types`

This is a fork of the lsp-types crate (gluon-lang/lsp-types) taken at version v0.95.1 (commit 3e6daee). This fork focuses usability improvements that make the types easier to work with for the Helix codebase. For example the URL type - the uri crate at this version of lsp-types - will be replaced with a wrapper around a string.