API Proposal: Make char.IsAscii public

[eiriktsarpalis]

System.Char currently defines a private IsAscii method. It think it might make sense to make this public?

public readonly struct Char
{
+  public static bool IsAscii(char ch);
}

[Dotnet-GitSync-Bot]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[eiriktsarpalis]

Not sure what the right area label for corelib stuff is.

[danmoseley]

Note there is already Rune.IsAscii(char) but it seems to me this is probably a case where duplication is reasonable, as the duplication is at a trivial level, and Rune is much less widely used than char; one might operate entirely on char and only need this one method on Rune.

[danmoseley]

@GrabYourPitchforks

[terrajobst]

Unless @GrabYourPitchforks has any objections, this feels like a sensible addition.

[GrabYourPitchforks]

We're also adding Ascii.IsAscii(char) (see #28230).

But I agree, targeted duplication like what's suggested here could help discoverability.