fix func declaration syntax

stdlib/funcs.go

@@ -24,9 +24,9 @@ import (
 
 func decl_func(input *ast.Token, vars ast.VarTable, funcs ast.FuncTable) *ast.Token {
     name := input
-    if name.Tag != ast.STRING {
+    if name.Tag != ast.SYMBOL {
         log.Log(log.ERR,
-            "non string handed to name arg",
+            "argument 1 of func must be a symbol to be exported",
             "func")
         return nil
     }