Defer need-check-nil and clean up stale suppressions

emmylua deserialises an unknown diagnostic code to a catch all that
matches no checker, so every `invisible`, `nil-check` and
`global-element` suppression was silently doing nothing. Renamed to the
emmylua codes. `name-style-check` has no equivalent and is dropped, it
was already disabled under luals.

The `get_tile` suppressions referenced an api typedef bug from 2024
which no longer reproduces.

need-check-nil is deferred rather than disabled on merit: a third of the
407 findings come from MapPosition and BoundingBox being aliased as
`struct|[double, double]`, so every `entity.position.x` reads as
possibly nil. The rest need per site knowledge of runtime invariants.

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

exp_commands/module/commands/rcon.lua

@@ -21,12 +21,10 @@ setmetatable(rcon_static, { __index = _G })
 setmetatable(rcon_env, { __index = rcon_static })
 
 --- Some common static values which can be added now
---- @diagnostic disable: name-style-check
 rcon_static.Async = Async
 rcon_static.ExpUtil = ExpUtil
 rcon_static.Commands = Commands
 rcon_static.print = Commands.print
---- @diagnostic enable: name-style-check
 
 --- Some common callback values which are useful when a player uses the command
 --- @alias ExpCommand.RconDynamic fun(player: LuaPlayer?): any