Add rfcbot to the bots used in the reference repo

Author: Urgau

repos/rust-lang/reference.toml

@@ -2,7 +2,7 @@ org = "rust-lang"
 name = "reference"
 description = "The Rust Reference"
 homepage = "https://doc.rust-lang.org/nightly/reference/"
-bots = ["rustbot"]
+bots = ["rustbot", "rfcbot"]
 
 [access.teams]
 lang = "write"