Include additional structured information in error objects

Thanks for this library, its the only one I've found with useful, descriptive error handling besides the DOMParser.

Would it be possible to extend the error object to break down the message a bit more? What I have in mind is to go from this:

Unclosed start tag for element `text` (line 1, column 243) iddle text-anchor="middle" font-size="200px" fill= ^ 

To this:

{
  errorCode: 0,
  message: Unclosed start tag for element,
  element: 'text',
  line: 1,
  col, 243,
  snippet: `middle text-anchor="middle" font-size="200px" fill=`
}

I know some of those entries are already in the object, which is great. Having the extra ones, like errorCode, message and element or similar would help with UI work.

The issue names no files, entry points, or tests. Start by locating the current error-object implementation and its tests, then determine which structured fields already exist and how errors are constructed. Done means agreeing on a stable schema and exposing the requested error code, message, element, location, and snippet information.