Validation errors should move cursor to the line

I clicked "Validate" and it says "Line 395: Duplicated tag". I can't count out 395 lines, I have to copy into Vim and do `g395` then go back and ctrl+f for the given line. It should automatically move the cursor to the line of the first error with [`setSelectionRange()`](https://developer.mozilla.org/en-US/docs/Web/API/HTMLTextAreaElement/setSelectionRange).