set_text
Description:
Sets the text of the layout.
This function validates text and renders invalid UTF-8 with a placeholder glyph.
Note that if you have used [method@Pango.Layout.set_markup] or [method@Pango.Layout.set_markup_with_accel] on this before, you may want to call [method@Pango.Layout.set_attributes] to clear the attributes set on the layout from the markup as this function does not clear attributes.
Parameters:
| this | a `PangoLayout` | 
| text | the text | 
| length | maximum length of  |