Set RFC number

Author: joshtriplett

text/0000-avoid-nonlocal-definitions-in-fns.md renamed to text/3373-avoid-nonlocal-definitions-in-fns.md

@@ -1,6 +1,6 @@
 - Feature Name: N/A
 - Start Date: 2022-01-19
-- RFC PR: [rust-lang/rfcs#0000](https://github.com/rust-lang/rfcs/pull/0000)
+- RFC PR: [rust-lang/rfcs#3373](https://github.com/rust-lang/rfcs/pull/3373)
 - Rust Issue: [rust-lang/rust#0000](https://github.com/rust-lang/rust/issues/0000)
 
 # Summary