Switch from cargo-machete to cargo-shear (#62643)

This results in ~110 crates being removed, and some orphaned files also.

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Release Notes:

- N/A

Signed-off-by: Neel <neel@zed.dev>

crates/copilot/Cargo.toml

@@ -47,9 +47,6 @@ sum_tree.workspace = true
 util.workspace = true
 workspace.workspace = true
 
-[target.'cfg(windows)'.dependencies]
-async-std.workspace = true
-
 [dev-dependencies]
 collections = { workspace = true, features = ["test-support"] }
 editor = { workspace = true, features = ["test-support"] }