Removed wrong rationale

Author: mildm8nnered

Source/SwiftLintBuiltInRules/Rules/Performance/ContainsOverFirstNotNilRule.swift

@@ -8,10 +8,6 @@ struct ContainsOverFirstNotNilRule: Rule {
         identifier: "contains_over_first_not_nil",
         name: "Contains over First not Nil",
         description: "Prefer `contains` over `first(where:) != nil` and `firstIndex(where:) != nil`.",
-        rationale: """
-        `filter` always needs to scan the entire collection, whereas `contains` can exit early as
-        soon as a match is found.
-        """,
         kind: .performance,
         nonTriggeringExamples: ["first", "firstIndex"].flatMap { method in
             [