Implement edition-based macro pat feature

compiler/rustc_span/src/symbol.rs

@@ -470,6 +470,7 @@ symbols! {
         dropck_parametricity,
         dylib,
         dyn_trait,
+        edition_macro_pats,
         eh_catch_typeinfo,
         eh_personality,
         emit_enum,
@@ -808,6 +809,8 @@ symbols! {
         partial_ord,
         passes,
         pat,
+        pat2018,
+        pat2021,
         path,
         pattern_parentheses,
         phantom_data,