gboolean gtk_text_iter_forward_char ( GtkTextIter* iter )
iter forward by one character offset.
Note that images embedded in the buffer occupy 1 character slot, so
this function may actually move onto an image instead of a character,
if you have images in your buffer. If
iter is the end iterator or
one character before it,
iter will now point at the end iterator,
and this function returns
FALSE for convenience when writing loops.