defer and struct hooks

compiler/NubLang/Tokenization/Tokenizer.cs

@@ -23,6 +23,7 @@ public sealed class Tokenizer
         ["module"] = Symbol.Module,
         ["export"] = Symbol.Export,
         ["import"] = Symbol.Import,
+        ["defer"] = Symbol.Defer,
     };
 
     private static readonly Dictionary<char[], Symbol> Symbols = new()
@@ -58,6 +59,7 @@ public sealed class Tokenizer
         [[';']] = Symbol.Semi,
         [['%']] = Symbol.Percent,
         [['|']] = Symbol.Pipe,
+        [['@']] = Symbol.At,
     };
 
     private static readonly (char[] Pattern, Symbol Symbol)[] OrderedSymbols = Symbols