The Python guys have removed it, we should as well. In a C API, it makes kind of sense, because you may need to do things like
gtk_text_buffer_set_text(b, s+X, Y-X+1) to insert a string slice. But in Pike (and Python), string slices are part of the language, so you can just type b->set_text(s[X..Y]) instead. BTW, the documentation is also wrong, since it claims that you should UTF-8 encode the string before passing it to the method, which is (thankfully) a lie.
