Add a french translation guide

The purpose of this guide is to document the glossary, the rules used
and to help the translators.

source/contribute/translations.html.md

@@ -70,6 +70,10 @@ When translating Plume (and related projects), please try to follow these rules:
 The style of inclusive that is choosen is not very important (just try to keep coherent with what is already done).
 - Don't be too formal (but stay polite!).
 
+### Translation guides
+
+- [French translation guide](../translations_fr/)
+
 ---
 
 That's it, you know everything you need to translate Plume! Thank you for your help!

source/contribute/translations_fr.html.md

@@ -0,0 +1,18 @@
+---
+title: Guide stylistique
+icon: flag
+summary: 'Guide stylistiques et recommendations pour la traduction de Plume en français'
+time: 2 minutes
+---
+
+## Forme inclusive
+
+- employer des [mots épicènes](https://fr.wikipedia.org/wiki/Mot_%C3%A9pic%C3%A8ne)
+- employer le point médian: `musicien·nes`, `motivé·es`
+
+## Glossaire
+
+- email: e-mail
+- feed: flux
+- tag: étiquette
+- token: jeton