Add links to ATLAS and CERN to intro page.

docs/index.md

@@ -23,8 +23,8 @@ hide:
 
 # ATLAS Software Documentation
 
-Here you can find tutorials and guides written and reviewed by experts.
-These pages contain structured software documentation, and exist in addition to the [Computing TWiki](https://twiki.cern.ch/twiki/bin/viewauth/AtlasComputing/AtlasComputing) [internal].
+Here you can find tutorials and guides for using the software of the [ATLAS Experiment](https://atlas.cern/) at [CERN](https://home.cern/).
+These pages contain public structured software documentation, and exist in addition to the (internal) [Computing TWiki](https://twiki.cern.ch/twiki/bin/viewauth/AtlasComputing/AtlasComputing).
 
 <div class="intro-box" style="color: #31708f; background-color: #d9edf7; border-color: #bce8f1;" markdown>
 **New to ATLAS?**<br>