Fix duplicate class and annotation placement lint errors

Classes contributed to by more than one file now carry the `partial`
attribute. trains.lua declared its command as `ExpCommand_Artillery`,
which was a copy paste.

`Color.0` and `MapPosition.0` became `.struct` in fmtk 2.1.6.

emmylua rejects `@type` on a function statement or a `do` block, so
those are moved onto the local or replaced by `@param` and `@return`.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

exp_commands/module/commands/authorities.lua

@@ -10,7 +10,7 @@ The default permission authorities controlled by the flags: admin_only, system_o
 
 local Storage = require("modules/exp_util/storage")
 
-local Commands = require("modules/exp_commands") --- @class Commands
+local Commands = require("modules/exp_commands") --- @class (partial) Commands
 local add, allow, deny = Commands.add_permission_authority, Commands.status.success, Commands.status.unauthorised
 
 local authorities = {}