message: Update grammar to reflect required type signature for enum declarations.
diff: @@ -14,7 +14,7 @@ attribute\_decl = `attribute` ident | `"`ident`"` `;`
  type\_decl = ( `table` | `struct` ) ident metadata `{` field\_decl+ `}`
  -enum\_decl = ( `enum` ident [ `:` type ] | `union` ident ) metadata `{`
  +enum\_decl = ( `enum` ident `:` type | `union` ident ) metadata `{`
  commasep( enumval\_decl ) `}`
  root\_decl = `root_type` ident `;`
  