Fix false positives on redundant_objc_attribute rule when using nested types

[marcelofabri]

Fixes #2539

[marcelofabri]

@dirtydanee @JaviSoto could you take a look at this and see if it makes sense? I'm not super familiar with @objcMembers to be 100% sure this is right.

[SwiftLintBot]

	1 Warning
⚠️	This PR may need tests.

	12 Messages
📖	Linting Aerial with this PR took 2.2s vs 2.04s on master (7% slower)
📖	Linting Alamofire with this PR took 5.27s vs 4.33s on master (21% slower)
📖	Linting Firefox with this PR took 18.64s vs 14.94s on master (24% slower)
📖	Linting Kickstarter with this PR took 28.65s vs 22.66s on master (26% slower)
📖	Linting Moya with this PR took 2.73s vs 2.26s on master (20% slower)
📖	Linting Nimble with this PR took 2.79s vs 2.06s on master (35% slower)
📖	Linting Quick with this PR took 0.73s vs 0.66s on master (10% slower)
📖	Linting Realm with this PR took 5.29s vs 4.1s on master (29% slower)
📖	Linting SourceKitten with this PR took 1.54s vs 1.32s on master (16% slower)
📖	Linting Sourcery with this PR took 6.45s vs 5.42s on master (19% slower)
📖	Linting Swift with this PR took 46.19s vs 33.25s on master (38% slower)
📖	Linting WordPress with this PR took 25.46s vs 23.49s on master (8% slower)

Generated by 🚫 Danger

[dirtydanee]

@dirtydanee @JaviSoto could you take a look at this and see if it makes sense? I'm not super familiar with @objcMembers to be 100% sure this is right.

I think the updated implementation is pretty neat, and its a much better approach to only check the parent structure instead of iterating on the whole file on each declaration kind.

[JaviSoto]

Hey! Sorry it took me so long to reply. Yeah this code looks so much better! It also solves the scenario I posted on #2539:

@objcMembers
class Foo {
  @objc enum Bar { }
}

But if I add it to the "non triggering examples", it's passing now 👍

[jpsim]

Nice work!