Treat class field as special function (such as `type`)

Nobody has claimed this yet.

In Factorio, all the API classes have a `object_name` field (not function!), which identifies their class name, much like `type()` does for base types. We're currently handling this with a plugin that rewrites this from `obj.object_name` to look like `__object_name(obj)` which is then tagged as ```
"Lua.runtime.special": {
"__object_name": "type"
},
```, to get it to work properly in type-tests, but it would be nice to be able to indicate that a class field "acts like `type`" in this way directly.

Start by reviewing the existing plugin rewrite from obj.object_name to __object_name(obj) and the Lua.runtime.special mapping to type. Trace how type-tests consume that mapping, then verify that a direct class-field declaration preserves the same behavior without the rewrite.

Written by the indexing model from the issue text.