docs: local flags are not supported

Author: gruhn

equiv-checker.html

@@ -368,8 +368,8 @@ <h4>Supported syntax:</h4>
 
  <h4>Unsupported syntax:</h4>
  <ul>
- <li>RegExp flags: <code>g</code>, <code>i</code>, <code>m</code>, <code>s</code>, <code>u</code>, <code>y</code>
- </li>
+ <li>Global flags: <code>/.../g</code>, <code>/.../i</code>, <code>/.../m</code>, ...</li>
+ <li>Local flags: <code>(?i:...)</code>, ...</li>
  <li>Unicode property escapes: <code>\p{...}</code>, <code>\P{...}</code></li>
  <li>Backreferences: <code>\1</code>, <code>\2</code>, ...</li>
  <li>Lookbehind assertions: <code>(?&lt;=...)</code>, <code>(?&lt;!...)</code></li>