I think `isBlank` and `isWhitespace` are quite confusable.
What `isBlank` does is so simple that you can just do the `c == ' ' or c == '\t'`
check yourself but in a lot of cases you don't even want that.
`std.ascii` can't really know what you think "blank" means.
That's why I think it's better to remove it.
And again, it seems ambiguous considering that we have `isWhitespace`.
Next, it also deprecates `isGraph`.
It's the same as `isPrint(c) and c != ' '`, which I find confusing.
When something is printable, you can say it also has a *graph*ical representation.
Removing `isGraph` solves this possible confusion.
d178df773a