Fix mentions of equality comparison for collections

[svick]

For ICollection<T>.Contains and Remove, the relevant types are (I)EqualityComparer<T>, not (I)Comparer<T>.

For List<T> and Array, don't try to (badly) explain their behavior, instead link to EqualityComparer<T>.Default.

[dotnet-policy-service]

Tagging subscribers to this area: @dotnet/area-system-collections

[Copilot]

Pull request overview

This PR corrects documentation inaccuracies regarding equality comparison mechanisms in .NET collection types. The changes fix incorrect references to Comparer<T> and IComparer<T> (which are for ordering comparisons) by replacing them with the correct EqualityComparer<T> and IEqualityComparer<T> types (which are for equality comparisons). Additionally, the documentation for Array and List<T> methods is simplified to reference EqualityComparer<T>.Default instead of providing potentially misleading explanations about how equality is determined.

Changes:

• Corrected ICollection<T>.Contains and Remove documentation to reference equality comparers instead of ordering comparers
• Updated Array.IndexOf overloads documentation to link to EqualityComparer<T>.Default
• Updated List<T>.Contains and IndexOf documentation to link to EqualityComparer<T>.Default

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
xml/System/Array.xml	Updated six IndexOf method overload remarks to reference EqualityComparer<T>.Default instead of explaining Equals method behavior
xml/System.Collections.Generic/List`1.xml	Corrected Contains and IndexOf remarks to reference EqualityComparer<T>.Default
xml/System.Collections.Generic/ICollection`1.xml	Fixed incorrect references from Comparer<T>/IComparer<T> to EqualityComparer<T>/IEqualityComparer<T> in Contains and Remove remarks