Fix std::mem::drop rustdoc misleading statement
This is a bit misleading, we were discussing this with our Rust team and some people could think that the compiler does some special magic for this specific function and that's not true or well the compiler does something special but for every function.
The reality according to my understanding is that this is a normal function that takes ownership of the given value and as with every other function mir building injects Drop Terminators , drop elaboration refines this and then we would insert the corresponding drop glue, then potentially calling Drop::drop.
Not sure if it would be best to remove the sentence as this PR does or explaining something along the lines of the previous text.
1d3d73ee5a