Docs: Designate E0001 to "Unexpected test after runEnd" with examples

Ref https://qunitjs.com/api/QUnit/module/#E0001

docs/api/config/autostart.md

@@ -26,11 +26,22 @@ In the browser, QUnit by default waits for all `<script>`  elements to finish lo
 
 Set this property to `false` to instruct QUnit to wait longer, allowing you to load test files asynchronously. Remember to call [`QUnit.start()`](../QUnit/start.md) once you're ready for tests to begin running.
 
-If you asynchronously load test files _without_ disabling autostart, you may encounter this warning:
+## Examples
 
-<p class="note note--warning" markdown="1">**warning**: Unexpected test after runEnd.</p>
+### Error: Unexpected test after runEnd {#E0001}
+
+If tests are new tests defined after QUnit has finished its run, you may encounter this error:
+
+```
+Error: Unexpected test after runEnd.
+```
+
+If you load test files asynchronously, make sure to disable autostart and call [`QUnit.start()`](../QUnit/start.md) accordingly.
+
+If you encounter this error unrelated to autostart, it might be that you're dynamically registering a new [QUnit.test](./test.md) from inside a hook or event callback towards the end of the test run, such as `hooks.after()` or `QUnit.done()`. It is recommended to define dynamic tests via [`QUnit.begin()`](../callbacks/QUnit.begin.md) instead. ([#1663](https://github.com/qunitjs/qunit/issues/1663))
+
+To report global errors from a plugin or other integration layer, consider calling [QUnit.onUncaughtException()](../QUnit/onUncaughtException.md) instead.
 
-## Examples
 
 ### ESM Dynamic imports
 

src/test.js

@@ -63,7 +63,7 @@ export default function Test (settings) {
   // (Meaning the CI would pass despite the late-failing test).
   // Ref https://github.com/qunitjs/qunit/issues/1377
   if (config.pq.finished) {
-    throw new Error('Unexpected test after runEnd. To report errors, consider calling QUnit.onUncaughtException() instead.');
+    throw new Error('Unexpected test after runEnd. https://qunitjs.com/api/QUnit/module/#E0001');
   }
   if (!this.skip && typeof this.callback !== 'function') {
     const method = this.todo ? 'QUnit.todo' : 'QUnit.test';