Reads new contents for the editor from a stream. The return value is #t if there are no errors, #f otherwise. See also File Formats.
New data is inserted at the position indicated by start, or at the current position if start is 'start.
If overwrite-styles? is #f, then each style name in the loaded file that are already in the current style list keep its current styles. Otherwise, existing named styles are overwritten with specifications from the loaded file.