html: Add support for autoclosing of tags (#11761)

Fixes #5267 
TODO:
- [x] Publish our fork of vscode-langservers-extracted on GH and wire
that through as a language server of choice for HTML extension.
- [x] Figure out how to prevent edits made by remote participants from
moving the cursor of a host.

Release Notes:

- Added support for autoclosing of HTML tags in local projects.

crates/snippet/src/snippet.rs

@@ -2,7 +2,7 @@ use anyhow::{anyhow, Context, Result};
 use smallvec::SmallVec;
 use std::{collections::BTreeMap, ops::Range};
 
-#[derive(Default)]
+#[derive(Clone, Debug, Default, PartialEq)]
 pub struct Snippet {
     pub text: String,
     pub tabstops: Vec<TabStop>,