Update rationale

p4-16/spec/P4-16-spec.mdk

@@ -2585,12 +2585,9 @@ The table below lists all types that may appear as base types in a
 | a `type` name     | allowed            | allowed         |
 |-------------------|--------------------|-----------------|
 
-Rationale: `void` is not useful except for specifying a function or
-method that does not return anything, therefore there is no reason in
-aliasing it and it could be confusing. `match_kind` values are not
-useful to store in a variable, as they are only used to specify how
-to match fields in table search keys, which are all declared at
-compile time and the declaration does not contain type.
+Rationale: So far, no clear motivation for allowing `typedef` for `void`
+and `match_kind` was presented. Therefore, to be on the safe side this
+is disallowed.
 
 [^type_allowed]: `type B <name>` is allowed for a type name `B`
     defined via `typedef X B` if `type X <name>` is allowed.