docs: fix typo in panic_hook example (tokio-rs#2453)

Author: arifd

examples/examples/panic_hook.rs

@@ -30,7 +30,7 @@ fn main() {
             // On nightly Rust, where the `PanicInfo` type also exposes a
             // `message()` method returning just the message, we could record
             // just the message instead of the entire `fmt::Display`
-            // implementation, avoiding the duplciated location
+            // implementation, avoiding the duplicated location
             tracing::error!(
                 message = %panic,
                 panic.file = location.file(),