Avoid dependencies build errors on Windows (#7827)

This is a compilation of fixes for errors that appeared in dependent
crates in Windows.

- wezterm (zed-industries/wezterm#1)
- tree-sitter-svelte (Himujjal/tree-sitter-svelte#54)
- tree-sitter-uiua (shnarazk/tree-sitter-uiua#25)
- tree-sitter-haskell (I sent a PR, but upstream source is regenerated
and no longer errors.)

Release Notes:

- N/A

crates/copilot/Cargo.toml

@@ -38,6 +38,9 @@ smol.workspace = true
 theme.workspace = true
 util.workspace = true
 
+[target.'cfg(windows)'.dependencies]
+async-std = { version = "1.12.0", features = ["unstable"] }
+
 [dev-dependencies]
 clock.workspace = true
 collections = { workspace = true, features = ["test-support"] }