Rollup merge of #143092 - RalfJung:const-check-lifetime-ext, r=oli-obk

const checks for lifetime-extended temporaries: avoid 'top-level scope' terminology

This error recently got changed in rust-lang/rust#140942 to use the terminology of "top-level scope", but after further discussion in rust-lang/reference#1865 it seems the reference will not be using that terminology after all. So let's also remove it from the compiler again, and let's focus on what actually happens with these temporaries: their lifetime is extended until the end of the program.

r? ``@oli-obk`` ``@traviscross``

Author: matthiaskrgr