Standardize on canceled instead of cancelled (#36385)

Release Notes:

- N/A

crates/agent/src/thread.rs

@@ -5337,7 +5337,7 @@ fn main() {{
     }
 
     #[gpui::test]
-    async fn test_retry_cancelled_on_stop(cx: &mut TestAppContext) {
+    async fn test_retry_canceled_on_stop(cx: &mut TestAppContext) {
         init_test_settings(cx);
 
         let project = create_test_project(cx, json!({})).await;
@@ -5393,7 +5393,7 @@ fn main() {{
             "Should have no pending completions after cancellation"
         );
 
-        // Verify the retry was cancelled by checking retry state
+        // Verify the retry was canceled by checking retry state
         thread.read_with(cx, |thread, _| {
             if let Some(retry_state) = &thread.retry_state {
                 panic!(

crates/agent/src/tool_use.rs

@@ -137,7 +137,7 @@ impl ToolUseState {
     }
 
     pub fn cancel_pending(&mut self) -> Vec<PendingToolUse> {
-        let mut cancelled_tool_uses = Vec::new();
+        let mut canceled_tool_uses = Vec::new();
         self.pending_tool_uses_by_id
             .retain(|tool_use_id, tool_use| {
                 if matches!(tool_use.status, PendingToolUseStatus::Error { .. }) {
@@ -155,10 +155,10 @@ impl ToolUseState {
                         is_error: true,
                     },
                 );
-                cancelled_tool_uses.push(tool_use.clone());
+                canceled_tool_uses.push(tool_use.clone());
                 false
             });
-        cancelled_tool_uses
+        canceled_tool_uses
     }
 
     pub fn pending_tool_uses(&self) -> Vec<&PendingToolUse> {