Fix app.ini sample file link in docs (#3529)

Signed-off-by: Lauris Bukšis-Haberkorns <[email protected]>

Author: lafriks

docs/content/page/index.en-us.md

@@ -74,7 +74,7 @@ Windows, on architectures like amd64, i386, ARM, PowerPC, and others.
         - MSSQL
         - TiDB (experimental, not recommended)
     - Configuration file
-        - [app.ini](https://github.com/go-gitea/gitea/blob/master/conf/app.ini)
+        - [app.ini](https://github.com/go-gitea/gitea/blob/master/custom/conf/app.ini.sample)
     - Admin panel
         - Statistics
         - Actions

docs/content/page/index.fr-fr.md

@@ -69,7 +69,7 @@ Le but de ce projet est de fournir de la manière la plus simple, la plus rapide
         - MSSQL
         - [TiDB](https://github.com/pingcap/tidb) (expérimental)
     - Fichier de configuration
-        - Voir [ici](https://github.com/go-gitea/gitea/blob/master/conf/app.ini)
+        - Voir [ici](https://github.com/go-gitea/gitea/blob/master/custom/conf/app.ini.sample)
     - Panel d'administration
         - Statistiques
         - Actions