Add release note

doc/manual/rl-next/debugger-on-trace.md

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+---
+synopsis: Enter the `--debugger` when `builtins.trace` is called if `builtins-trace-debugger` is set
+prs: 9914
+---
+
+If the `builtins-trace-debugger` option is set and `--debugger` is given,
+`builtins.trace` calls will behave similarly to `builtins.break` and will enter
+the debug REPL. This is useful for determining where warnings are being emitted
+from.