Insert the given attribute into the PangoAttrList.
It will replace any attributes of the same type on that segment
and be merged with any adjoining attributes that are identical.
This function is slower than [method@Pango.AttrList.insert] for
creating an attribute list in order (potentially much slower for
large lists). However, [method@Pango.AttrList.insert] is not
suitable for continually changing a set of attributes since it
never removes or combines existing attributes.
Insert the given attribute into the PangoAttrList.
It will replace any attributes of the same type on that segment and be merged with any adjoining attributes that are identical.
This function is slower than [method@Pango.AttrList.insert] for creating an attribute list in order (potentially much slower for large lists). However, [method@Pango.AttrList.insert] is not suitable for continually changing a set of attributes since it never removes or combines existing attributes.