Update .github/instructions/wants-processing.instructions.md

Co-authored-by: Tantek Çelik <[email protected]>

Author: aarongustafson

.github/instructions/wants-processing.instructions.md

@@ -151,6 +151,7 @@ related:
 **Related Links to Consider:**
 - W3C specifications and working drafts
 - WHATWG living standards  
+- IETF RFCs  
 - Browser vendor documentation
 - Established developer resources
 - GitHub repositories for standards work