Updated Installation on ReMarkable (markdown)

Installation-on-ReMarkable.md

@@ -1,7 +1,7 @@
 ## :warning: Known Issues
 
 - ReMarkable 2 support status: [now available](https://github.com/koreader/koreader/pull/6992#issuecomment-756667595)
-- Wi-Fi Network Manager: [not implemented](https://github.com/koreader/koreader/issues/6677)
+- Wi-Fi Network Manager: [now available](https://github.com/koreader/koreader/pull/7216#issue-564667653)
 
 ## Finding your IP and password