Rename RFC file

Author: tgross35

text/0000-feature-metadata.md renamed to text/3416-feature-metadata.md

@@ -1,6 +1,6 @@
 -   Feature Name: feature-metadata
 -   Start Date: 2023-04-14
--   RFC PR: [rust-lang/rfcs#0000](https://github.com/rust-lang/rfcs/pull/3416)
+-   RFC PR: [rust-lang/rfcs#3416](https://github.com/rust-lang/rfcs/pull/3416)
 -   Rust Issue: [rust-lang/rust#0000](https://github.com/rust-lang/rust/issues/0000)
 
 # Summary