enum fields with a type are not supported

the c++ codebase lets it slide

the self hosted parser correctly reports a parse error

Author: andrewrk

test/cases/syntax.zig

@@ -5,7 +5,6 @@ const struct_no_comma = struct { x: i32, y: i32 };
 const struct_fn_no_comma = struct { fn m() void {} y: i32 };
 
 const enum_no_comma = enum { A, B };
-const enum_no_comma_type = enum { A, B: i32 };
 
 fn container_init() void {
     const S = struct { x: i32, y: i32 };