ImmutableDictionary.WithComparers does not document its ArgumentException

### Type of issue

Missing information

### Description

Calling either overload of `ImmutableDictionary.WithComparers` can cause an `ArgumentException` if the new old key values collide when using the new key comparer. This should probably be documented.

### Page URL

https://learn.microsoft.com/en-us/dotnet/api/system.collections.immutable.immutabledictionary-2.withcomparers?view=net-8.0

### Content source URL

https://github.com/dotnet/dotnet-api-docs/blob/main/xml/System.Collections.Immutable/ImmutableDictionary`2.xml

### Document Version Independent Id

af3db283-6b11-5dca-a3e9-0d4e06ac661b

### Article author

@dotnet-bot