Fix broken link in documentation

The Arduino Library Manager documentation was moved to a new location without setting up a redirect, which broke this
link.

Author: per1234

FAQ.md

@@ -43,7 +43,7 @@ When a library is [added to the library list](README.md#adding-a-library-to-libr
 
 More information:
 
-- https://www.arduino.cc/en/Guide/Libraries#toc3
+- https://docs.arduino.cc/software/ide-v1/tutorials/installing-libraries#using-the-library-manager
 - https://arduino.github.io/arduino-cli/latest/commands/arduino-cli_lib/
 - https://create.arduino.cc/projecthub/Arduino_Genuino/getting-started-with-arduino-web-editor-on-various-platforms-4b3e4a
 

README.md

@@ -1,7 +1,7 @@
 # Arduino Library Manager list
 
 This repository contains the list of libraries in the
-[Arduino Library Manager](https://www.arduino.cc/en/guide/libraries#toc3) index.
+[Arduino Library Manager](https://docs.arduino.cc/software/ide-v1/tutorials/installing-libraries#using-the-library-manager) index.
 
 ## Table of Contents