[ErrorHandler] fix html W3C compliance

Author: awoimbee

Extension/CodeExtension.php

@@ -137,7 +137,7 @@ public function fileExcerpt(string $file, int $line, int $srcContext = 3): ?stri
             }
 
             for ($i = max($line - $srcContext, 1), $max = min($line + $srcContext, \count($content)); $i <= $max; ++$i) {
-                $lines[] = '<li'.($i == $line ? ' class="selected"' : '').'><a class="anchor" name="line'.$i.'"></a><code>'.self::fixCodeMarkup($content[$i - 1]).'</code></li>';
+                $lines[] = '<li'.($i == $line ? ' class="selected"' : '').'><a class="anchor" id="line'.$i.'"></a><code>'.self::fixCodeMarkup($content[$i - 1]).'</code></li>';
             }
 
             return '<ol start="'.max($line - $srcContext, 1).'">'.implode("\n", $lines).'</ol>';