std.uni.CodepointSet from range of pairs of integers

[Richard (Rikki) Andrew Cattermole]

I can understand ``pure``.

https://github.com/dlang/phobos/blob/master/std/uni/package.d#L2075

It is literally on the constructor.

Now @safe I don't know. My best guess would be for some reason the 
constructor is getting inferred as it (templates get inferred).