Uncomment binarySearchBy overload taking a Comparator

[YoshiRulz]

• provided the link to the related issue(s) from YouTrack N/A
• made a reasonable amount of changes related only to the provided issues
• can explain changes made in the pull request
  • I was looking for this overload and noticed the comment upon jumping to the source of another overload. Turns out it's as old as the initial implementation. Having this overload in the standard library "completes the family", and it's useful to at least me. I'm rolling my own copy with the same implementation for now.
• ran the build locally and verified new functionality
• ran related tests locally and they passed
• do not have merge commits in the pull request

[ilya-g]

Could you describe your use case where you needed to use this overload? This would also be useful in case we want to provide a separate sample for this overload.

[YoshiRulz]

In short, I had a sorted list whose elements were data class Domain(val raw: CharSequence, val type: TypeEnum) and I needed to get the type of the element matching an input string. CharSequence is not Comparable so I couldn't use the other overload taking a selector function. The other option I considered was populating a Map<CharSequence, Domain>, which would probably have been about as performant, though it now occurs to me that it may not have given me the comparison I was after.