addInsertion abstract method
Add an insertion of text at the given offset. The offset is relative
to the original source. The buildEdit function is used to write the text
to be inserted. This is fully equivalent to
addReplacement(new SourceRange(offset, 0), buildEdit);
Implementation
@override
// TODO(srawlins): Rename to `insert`.
void addInsertion(
int offset,
void Function(DartEditBuilder builder) buildEdit,
);