Comparer<T> code snippet issues

[svee4]

https://learn.microsoft.com/en-us/dotnet/api/system.collections.generic.comparer-1?view=net-8.0#examples

In the examples code snippet, the comment above the declaration of LengthFirst talks about an explicit interface implementation, but I don't see this anywhere in the snippet.

The snippet has some other issues too, including:

1. Local variables named in pascal case (Boxes, LengthFirst, BoxA and BoxB)
2. Ancient string formatting (should be using string interpolation instead)
3. Unused variables (defComp, bc)
4. Weird variable names (why bx instead of box, why defComp instead of defaultComparer, what is bc?)
5. The Compare methods could use some variables for clarity and code quality
6. Use collection expression for creating the list

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