Add some more rule rationales

[mildm8nnered]

[SwiftLintBot]

	1 Warning
:warning:	If this is a user-facing change, please include a CHANGELOG entry to credit yourself! You can find it at CHANGELOG.md.

	19 Messages
:book:	Building this branch resulted in the same binary size as when built on main.
:book:	Linting Aerial with this PR took 0.17 s vs 0.2 s on main (15% faster).
:book:	Linting Alamofire with this PR took 0.19 s vs 0.23 s on main (17% faster).
:book:	Linting Brave with this PR took 0.99 s vs 1.01 s on main (1% faster).
:book:	Linting DuckDuckGo with this PR took 3.41 s vs 3.4 s on main (0% slower).
:book:	Linting Firefox with this PR took 1.72 s vs 1.72 s on main (0% slower).
:book:	Linting Kickstarter with this PR took 1.0 s vs 1.03 s on main (2% faster).
:book:	Linting Moya with this PR took 0.12 s vs 0.13 s on main (7% faster).
:book:	Linting NetNewsWire with this PR took 0.39 s vs 0.39 s on main (0% slower).
:book:	Linting Nimble with this PR took 0.19 s vs 0.18 s on main (5% slower).
:book:	Linting PocketCasts with this PR took 1.07 s vs 1.06 s on main (0% slower).
:book:	Linting Quick with this PR took 0.13 s vs 0.13 s on main (0% slower).
:book:	Linting Realm with this PR took 0.53 s vs 0.52 s on main (1% slower).
:book:	Linting Sourcery with this PR took 0.35 s vs 0.35 s on main (0% slower).
:book:	Linting Swift with this PR took 0.62 s vs 0.6 s on main (3% slower).
:book:	Linting SwiftLintPerformanceTests with this PR took 3.81 s vs 3.75 s on main (1% slower).
:book:	Linting VLC with this PR took 0.32 s vs 0.27 s on main (18% slower).
:book:	Linting Wire with this PR took 2.33 s vs 2.32 s on main (0% slower).
:book:	Linting WordPress with this PR took 1.63 s vs 1.63 s on main (0% slower).

Here's an example of your CHANGELOG entry:

* Add some more rule rationales.  
  [mildm8nnered](https://github.com/mildm8nnered)
  [#issue_number](https://github.com/realm/SwiftLint/issues/issue_number)

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