Port System.Collections new docs

[directhex]

@dotnet/area-system-collections @carlossanlop @gewarren PTAL

[dotnet-policy-service]

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

[eiriktsarpalis]

cc @stephentoub who contributed some of the new collection types.

[learn-build-service-prod]

Learn Build status updates of commit fc40091:

✅ Validation status: passed

File	Status	Preview URL	Details
xml/System.Collections.Generic/Dictionary`2.xml	✅Succeeded	View
xml/System.Collections.Generic/Dictionary2+AlternateLookup1.xml	✅Succeeded	View
xml/System.Collections.Generic/HashSet`1.xml	✅Succeeded	View
xml/System.Collections.Generic/HashSet1+AlternateLookup1.xml	✅Succeeded	View
xml/System.Collections.Generic/IAlternateEqualityComparer`2.xml	✅Succeeded	View
xml/System.Collections.Generic/OrderedDictionary`2.xml	✅Succeeded	View
xml/System.Collections.Generic/OrderedDictionary`2+Enumerator.xml	✅Succeeded	View
xml/System.Collections.Generic/OrderedDictionary`2+KeyCollection.xml	✅Succeeded	View
xml/System.Collections.Generic/OrderedDictionary`2+KeyCollection+Enumerator.xml	✅Succeeded	View
xml/System.Collections.Generic/OrderedDictionary`2+ValueCollection.xml	✅Succeeded	View
xml/System.Collections.Generic/OrderedDictionary`2+ValueCollection+Enumerator.xml	✅Succeeded	View
xml/System.Collections.Generic/Queue`1.xml	✅Succeeded	View
xml/System.Collections.ObjectModel/ReadOnlySet`1.xml	✅Succeeded	View

For more details, please refer to the build report.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
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[carlossanlop]

@directhex consider applying all suggestions in batch (one commit for all) instead of one by one (one commit per suggestion).

[learn-build-service-prod]

Learn Build status updates of commit b6ab5f1:

✅ Validation status: passed

File	Status	Preview URL	Details
xml/System.Collections.Generic/Dictionary`2.xml	✅Succeeded	View
xml/System.Collections.Generic/Dictionary2+AlternateLookup1.xml	✅Succeeded	View
xml/System.Collections.Generic/HashSet`1.xml	✅Succeeded	View
xml/System.Collections.Generic/HashSet1+AlternateLookup1.xml	✅Succeeded	View
xml/System.Collections.Generic/IAlternateEqualityComparer`2.xml	✅Succeeded	View
xml/System.Collections.Generic/OrderedDictionary`2.xml	✅Succeeded	View
xml/System.Collections.Generic/OrderedDictionary`2+Enumerator.xml	✅Succeeded	View
xml/System.Collections.Generic/OrderedDictionary`2+KeyCollection.xml	✅Succeeded	View
xml/System.Collections.Generic/OrderedDictionary`2+KeyCollection+Enumerator.xml	✅Succeeded	View
xml/System.Collections.Generic/OrderedDictionary`2+ValueCollection.xml	✅Succeeded	View
xml/System.Collections.Generic/OrderedDictionary`2+ValueCollection+Enumerator.xml	✅Succeeded	View
xml/System.Collections.Generic/Queue`1.xml	✅Succeeded	View
xml/System.Collections.ObjectModel/ReadOnlySet`1.xml	✅Succeeded	View

For more details, please refer to the build report.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
• Post your question in the Learn support channel

[learn-build-service-prod]

Learn Build status updates of commit 04be420:

✅ Validation status: passed

File	Status	Preview URL	Details
xml/System.Collections.Generic/Dictionary`2.xml	✅Succeeded	View
xml/System.Collections.Generic/Dictionary2+AlternateLookup1.xml	✅Succeeded	View
xml/System.Collections.Generic/HashSet`1.xml	✅Succeeded	View
xml/System.Collections.Generic/HashSet1+AlternateLookup1.xml	✅Succeeded	View
xml/System.Collections.Generic/IAlternateEqualityComparer`2.xml	✅Succeeded	View
xml/System.Collections.Generic/OrderedDictionary`2.xml	✅Succeeded	View
xml/System.Collections.Generic/OrderedDictionary`2+Enumerator.xml	✅Succeeded	View
xml/System.Collections.Generic/OrderedDictionary`2+KeyCollection.xml	✅Succeeded	View
xml/System.Collections.Generic/OrderedDictionary`2+KeyCollection+Enumerator.xml	✅Succeeded	View
xml/System.Collections.Generic/OrderedDictionary`2+ValueCollection.xml	✅Succeeded	View
xml/System.Collections.Generic/OrderedDictionary`2+ValueCollection+Enumerator.xml	✅Succeeded	View
xml/System.Collections.Generic/Queue`1.xml	✅Succeeded	View
xml/System.Collections.ObjectModel/ReadOnlySet`1.xml	✅Succeeded	View

For more details, please refer to the build report.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
• Post your question in the Learn support channel