this remains true (rust-lang#1620)

Author: tshepang

src/doc/rustc-dev-guide/src/diagnostics/diagnostic-items.md

@@ -48,7 +48,7 @@ A new diagnostic item can be added with these two steps:
     For the naming conventions of diagnostic items, please refer to
     [*Naming Conventions*](#naming-conventions).
 
-2. <!-- date-check: Aug 2022 -->
+2. <!-- date-check: Feb 2023 -->
    Diagnostic items in code are accessed via symbols in
    [`rustc_span::symbol::sym`].
    To add your newly-created diagnostic item,