docs: add documentation for the socket.recovered attribute

Author: darrachequesne

docs/categories/01-Documentation/connection-state-recovery.md

@@ -58,7 +58,7 @@ io.on("connection", (socket) => {
 ```js
 socket.on("connect", () => {
   if (socket.recovered) {
-    // any missed packets will be received
+    // any event missed during the disconnection period will be received now
   } else {
     // new or unrecoverable session
   }

docs/client-api.md

@@ -492,6 +492,26 @@ socket.on("connect", () => {
 });
 ```
 
+#### socket.recovered
+
+*Added in v4.6.0*
+
+- [`<boolean>`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#boolean_type)
+
+Whether the connection state was successfully recovered during the last reconnection.
+
+```js
+socket.on("connect", () => {
+  if (socket.recovered) {
+    // any event missed during the disconnection period will be received now
+  } else {
+    // new or unrecoverable session
+  }
+});
+```
+
+More information about this feature [here](../docs/categories/01-Documentation/connection-state-recovery.md).
+
 ### Methods
 
 #### socket.close()

docs/server-api.md

@@ -1727,6 +1727,26 @@ See also:
 
 :::
 
+#### socket.recovered
+
+*Added in v4.6.0*
+
+- [`<boolean>`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#boolean_type)
+
+Whether the connection state was successfully recovered during the last reconnection.
+
+```js
+io.on("connection", (socket) => {
+  if (socket.recovered) {
+    // recovery was successful: socket.id, socket.rooms and socket.data were restored
+  } else {
+    // new or unrecoverable session
+  }
+});
+```
+
+More information about this feature [here](../docs/categories/01-Documentation/connection-state-recovery.md).
+
 #### socket.request
 
 * [`<http.IncomingMessage>`](https://nodejs.org/api/http.html#class-httpincomingmessage)

src/pages/how-to/implement-a-subscription-model.md

@@ -121,3 +121,5 @@ socket.on("connect", () => {
 The `!socket.recovered` condition is related to the [Connection state recovery feature](/docs/v4/connection-state-recovery).
 
 If the connection state was successfully recovered, then the subscriptions (the rooms on the server side) will be automatically restored.
+
+Reference: [`socket.recovered` attribute](/docs/v4/client-api/#socketrecovered)