code: private static function highlightSourceAtLocation(Source $source, SourceLocation $location)
      {
          $line          = $location->line;
          $lineOffset    = $source->locationOffset->line - 1;
          $columnOffset  = self::getColumnOffset($source, $location);
          $contextLine   = $line + $lineOffset;
          $contextColumn = $location->column + $columnOffset;
          $prevLineNum   = (string) ($contextLine - 1);
          $lineNum       = (string) $contextLine;
          $nextLineNum   = (string) ($contextLine + 1);
          $padLen        = strlen($nextLineNum);
          $lines         = preg_split('/\r\n|[\n\r]/', $source->body);
  
          $lines[0] = self::whitespace($source->locationOffset->column - 1) . $lines[0];
  
          $outputLines = [
              sprintf('%s (%s:%s)', $source->name, $contextLine, $contextColumn),
              $line >= 2 ? (self::lpad($padLen, $prevLineNum) . ': ' . $lines[$line - 2]) : null,
              self::lpad($padLen, $lineNum) . ': ' . $lines[$line - 1],
              self::whitespace(2 + $padLen + $contextColumn - 1) . '^',
              $line < count($lines) ? self::lpad($padLen, $nextLineNum) . ': ' . $lines[$line] : null,
          ];
  
          return implode("\n", array_filter($outputLines));
      }
docs: Render a helpful description of the location of the error in the GraphQL
  Source document.
  
  @return string