Copy FetchBaseQueryError type into docs

Author: markerikson

docs/rtk-query/api/fetchBaseQuery.mdx

@@ -83,14 +83,60 @@ type FetchBaseQueryResult = Promise<
       meta?: { request: Request; response: Response }
     }
   | {
-      error: {
-        status: number
-        data: any
-      }
+      error: FetchBaseQueryError
       data?: undefined
       meta?: { request: Request; response: Response }
     }
 >
+
+type FetchBaseQueryError =
+  | {
+      /**
+       * * `number`:
+       *   HTTP status code
+       */
+      status: number
+      data: unknown
+    }
+  | {
+      /**
+       * * `"FETCH_ERROR"`:
+       *   An error that occurred during execution of `fetch` or the `fetchFn` callback option
+       **/
+      status: 'FETCH_ERROR'
+      data?: undefined
+      error: string
+    }
+  | {
+      /**
+       * * `"PARSING_ERROR"`:
+       *   An error happened during parsing.
+       *   Most likely a non-JSON-response was returned with the default `responseHandler` "JSON",
+       *   or an error occurred while executing a custom `responseHandler`.
+       **/
+      status: 'PARSING_ERROR'
+      originalStatus: number
+      data: string
+      error: string
+    }
+  | {
+      /**
+       * * `"TIMEOUT_ERROR"`:
+       *   Request timed out
+       **/
+      status: 'TIMEOUT_ERROR'
+      data?: undefined
+      error: string
+    }
+  | {
+      /**
+       * * `"CUSTOM_ERROR"`:
+       *   A custom error type that you can return from your `queryFn` where another error might not make sense.
+       **/
+      status: 'CUSTOM_ERROR'
+      data?: unknown
+      error: string
+    }
 ```
 
 ## Parameters