Rollup merge of rust-lang#39454 - abonander:proc_macro_tracking_issue, r=jseyfried

Change tracking issue for `proc_macro` feature to rust-lang#38356

r? @jseyfried

Author: frewsxcv

src/libsyntax/feature_gate.rs

@@ -318,7 +318,7 @@ declare_features! (
     (active, abi_unadjusted, "1.16.0", None),
 
     // Macros 1.1
-    (active, proc_macro, "1.16.0", Some(35900)),
+    (active, proc_macro, "1.16.0", Some(38356)),
 
     // Allows attributes on struct literal fields.
     (active, struct_field_attributes, "1.16.0", Some(38814)),