Code editor is difficult to use in iOS Safari

In Safari in iOS, it's difficult to delete text in the Try Purescript! code window. Backspace seems to be the only option. I gather that this is due to some interaction between the Ace editor and iOS or Safari. (This makes issue #309 more important in this context.)

It would be nice to be able to try out Purescript on an iPad. On a real computer, you always have the option of installing Purescript, so in some ways it's more important to be able to use Try Purescript! on a tablet.

Obviously, it's unlikely that one would do real work in Try Purescript! on a tablet, but it would be nice to able to play around with the language. At present, you have to be pretty desperate to do that in iOS Safari.

Maybe I'm missing way of interacting with the editor, but I tried the usual tricks, I think. (Maybe other browsers for iOS are better, but Safari is the default, obviously.)

Start by reproducing the deletion problem in the Try Purescript! code window using Safari on iOS, then inspect the Ace editor integration. Compare the editor's behavior with the usual text-editing interactions described in the issue. Done means text can be deleted normally in iOS Safari without regressing the existing editor behavior.