Explain index as key can be ok

The pitfall warning on https://beta.reactjs.org/learn/rendering-lists states that using index or random for keys is bad. However, this is the only mention of using indexes of keys. I think it should state that using indexes is bad, but it should also be clear that using random values much worse.

The problem is using index as key is a well known anti-pattern in the React world. People come up with much worse solutions, e.g. use a random key, to get rid of ESLint warnings.

Also there are legitimate use cases for an index as a key, for example when rendering a static list of data. I think this should be acknowledged in the Where to get your key section.

Ouvre la page Rendering Lists à l’adresse https://beta.reactjs.org/learn/rendering-lists et lis l’avertissement sur les pièges ainsi que la section « Where to get your key ». Mets à jour l’explication afin qu’elle distingue les clés basées sur l’index des clés aléatoires et qu’elle reconnaisse les listes statiques comme un cas légitime d’utilisation de clés basées sur l’index ; c’est terminé lorsque les indications sont claires et cohérentes aux deux endroits.