types/description: add support for make_description<void>

types/description.hpp

@@ -70,10 +70,17 @@ namespace cruft::types {
     constexpr description
     make_description (void) noexcept
     {
-        return {
-            .category = category_traits_v<T>,
-            .width = sizeof (T)
-        };
+        if constexpr (std::is_void_v<T>) {
+            return {
+                .category = category::NONE,
+                .width    = 0,
+            };
+        } else {
+            return {
+                .category = category_traits_v<T>,
+                .width = sizeof (T)
+            };
+        }
     }