Collect the plural name of content types

Many times in building sites I have needed the plural name of a content type ("Blog posts" rather than "Blog post") - for example in listing titles/links, breadcrumbs, paths or help text. This often gets hardcoded or recorded in configuration in multiple places but it occurred to me that the right place to collect this information is on the content type page itself.

Obviously this can be easily done with a contrib module, but I think that it is highly likely that we could use this functionality in core when some basic default views-type functionality, and perhaps also to clean up some the places where the plural form is being hardcoded in core and can only be changed using locale module on multiple strings (for example if you wanted Blog post/Blog posts to be Journal entry/Journal entries) which is quite non-intuitive for such a simple request.

A rough patch is attached - feedback welcome!