If sourceSpan is available, this contains the spans of each attribute.
The span of an attribute is the entire attribute, including the name and
quotes (if any). For example, the span of "attr" in <a attr="value">
would be the text attr="value".
If sourceSpan is available, this contains the spans of each attribute's
value. Unlike attributeSpans, this span will include only the value.
For example, the value span of "attr" in <a attr="value"> would be the
text value.