Slightly improve doc about mail forward

Author: Jojo144

docs/admin/35.email/index.mdx

@@ -28,7 +28,7 @@ Desktop and mobile clients have the advantage of copying your emails to the devi
 
 ## Configuring email aliases and auto-forwards
 
-Mail aliases and forwards can be configured for each users. For instance, the first user created on the server automatically has an alias `root@the.domain.tld` configured - meaning that an email sent to this address will end in the inbox of the first user. Automatic forwards may be configured, for instance if an user doesn't want to configure an additional email account and just wants to receive emails from the server on, say, his/her gmail address.
+Mail aliases and forwards can be configured for each users. For instance, the first user created on the server automatically has an alias `root@the.domain.tld` configured - meaning that an email sent to this address will end in the inbox of the first user. Automatic forwards may be configured, for instance if an user doesn't want to configure an additional email account and just wants to receive emails from the server on, say, his/her gmail address (a copy of each mail will be kept on the Yunohost server).
 
 Another feature which few people know about is the use of suffixes beginning with "+". For example, emails sent to `johndoe+booking@the.domain.tld` will automatically land in the `booking` dir (lowercase) of John Doe's mailbox or in John Doe's inbox if `booking` directory doesn't exist . It is a practical technique for example to provide an e-mail address to a website, then easily sort (via automatic filters) the mail coming from this website.