Prepare RFC 3373 for merge

RFC 3373 has been accepted.  We've created the tracking issue.  Let's
add that to the RFC.

Author: traviscross

text/3373-avoid-nonlocal-definitions-in-fns.md

@@ -1,7 +1,7 @@
 - Feature Name: N/A
 - Start Date: 2022-01-19
 - 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)
+- Tracking Issue: [rust-lang/rust#120363](https://github.com/rust-lang/rust/issues/120363)
 
 # Summary
 [summary]: #summary