Use tool calling instead of XML parsing to generate edit operations (#15385)

Release Notes:

- N/A

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Co-authored-by: Nathan <nathan@zed.dev>

crates/assistant/Cargo.toml

@@ -75,7 +75,6 @@ util.workspace = true
 uuid.workspace = true
 workspace.workspace = true
 picker.workspace = true
-roxmltree = "0.20.0"
 
 [dev-dependencies]
 completion = { workspace = true, features = ["test-support"] }