Enable triagebot note functionality for rust-lang/rust

See <https://forge.rust-lang.org/triagebot/note.html>.

Author: jieyouxu

triagebot.toml

@@ -1397,3 +1397,7 @@ compiletest = [
 # Enable issue transfers within the org
 # Documentation at: https://forge.rust-lang.org/triagebot/transfer.html
 [transfer]
+
+# Enable `@rustbot note` functionality
+# Documentation at: https://forge.rust-lang.org/triagebot/note.html
+[note]