docs: document onWebViewRecreated and onWebViewRecreatedListener

Author: Fandroid745

AnkiDroid/src/main/java/com/ichi2/anki/workarounds/SafeWebViewLayout.kt

@@ -217,6 +217,27 @@ open class SafeWebViewLayout :
     }
 }
 
+/**
+ * It is called by [SafeWebViewLayout.onRenderProcessGone] after its internal [WebView] is replaced,
+ * due to a render process crash or the system killing it to free memory.
+ *
+ * The host [Fragment] must always implement this interface. In debug builds a missing implementation
+ * will throw at [SafeWebViewLayout.onAttachedToWindow]
+ */
 fun interface OnWebViewRecreatedListener {
+    /**
+     * It is called by [SafeWebViewLayout.onRenderProcessGone] with the new [WebView] after
+     * the old instance has been removed and destroyed. The implementations must reapply
+     * all the clients,settings and content that were configured on the original [WebView]
+     * because the previous configuration is not retained.
+     *
+     *`super.onWebviewRecreated(webview)` must be called when overriding this method in a subclass.
+     *
+     * To manually trigger this path,call `webviewLayout.loadUrl("chrome://crash")`.
+     * Automated testing would require an instrumentation test, a unit test is not sufficient.
+     *
+     *
+     * @param webView the new [webView],already attached to [SafeWebViewLayout]
+     */
     fun onWebViewRecreated(webView: WebView)
 }