docs: address review feedback

- Soften the $_ENV note: state the current behavior without claiming a performance rationale.
- Simplify the state-persistence example loop.
- Clarify that Symfony and Laravel Octane reset most state, but user services may need to implement Symfony's ResetInterface.
- Add a `text` language to fenced state-machine and protocol diagrams in internals.md to satisfy markdownlint MD040.

Signed-off-by: Kévin Dunglas <kevin@dunglas.fr>

Author: dunglas

docs/internals.md

@@ -54,7 +54,7 @@ Each thread has a `ThreadState` (defined in `internal/state/state.go`) that gove
 
 ### States
 
-```
+```text
 Lifecycle:        Reserved → Booting → Inactive → Ready ⇄ (processing)
                                                     ↓
 Shutdown:                                     ShuttingDown → Done → Reserved
@@ -98,7 +98,7 @@ This guarantees mutual exclusion: only one of `shutdown()`, `setHandler()`, or `
 
 When a thread needs to change its handler (e.g., from inactive to worker):
 
-```
+```text
 Go side (setHandler)           C side (PHP thread)
 ─────────────────              ─────────────────
 RequestSafeStateChange(
@@ -121,7 +121,7 @@ This protocol ensures the handler pointer is never read and written concurrently
 
 When workers are restarted (e.g., via admin API):
 
-```
+```text
 Go side (RestartWorkers)       C side (worker thread)
 ─────────────────              ─────────────────
 RequestSafeStateChange(

docs/worker.md

@@ -170,7 +170,7 @@ $handler = static function () use ($workerServer) {
 ```
 
 Most superglobals (`$_GET`, `$_POST`, `$_COOKIE`, `$_FILES`, `$_SERVER`, `$_REQUEST`) are automatically reset between requests.
-However, **`$_ENV` is not reset between requests** for performance reasons.
+However, **`$_ENV` is currently not reset between requests**.
 This means that any modifications made to `$_ENV` during a request will persist and be visible to subsequent requests handled by the same worker thread.
 Avoid storing request-specific or sensitive data in `$_ENV`.
 
@@ -196,10 +196,10 @@ $handler = static function () {
     echo getCounter(); // 1, 2, 3, ... for each request on this thread
 };
 
-for ($nbRequests = 0; ; ++$nbRequests) {
-    if (!\frankenphp_handle_request($handler)) break;
+while (\frankenphp_handle_request($handler)) {
+    // ...
 }
 ```
 
-When writing worker scripts, make sure to reset any request-specific state at the beginning of each request handler.
-Frameworks like [Symfony](symfony.md) and [Laravel Octane](laravel.md) handle this automatically.
+When writing worker scripts, make sure to reset any request-specific state between requests.
+Frameworks like [Symfony](symfony.md) and [Laravel Octane](laravel.md) take care of resetting most state for you, but you may still need to reset your own services. With Symfony, services that hold request-specific state should implement [`Symfony\Contracts\Service\ResetInterface`](https://github.com/symfony/contracts/blob/main/Service/ResetInterface.php) so they're reset by the kernel between requests.