Fix placeholder lines returned from LocalServer

[oferb]

Local server marks lines as changed not by them actual number, but by number after adding placeholders (blue numbers on the pic).

Line 27 isn't highlighted, because placeholder 31 is highlighted instead.
Temporary front-end method, which fixes the issue:

tempFixChangesLineNumber(textChanges: TextChange[]): void {
  let delimiter: number = 0;
  textChanges.forEach(textChange => {
    switch (textChange.getType()) {
      case ChangeType.DELETE:
      case ChangeType.ADD:
        textChange.setLineNumber(textChange.getLineNumber() - delimiter);
        break;
      case ChangeType.LINE_PLACEHOLDER:
        delimiter++;
    }
  });
}