fix typo in description of helo_name (#6194)

fix(config): also correct typo in config.rs

.env.template

@@ -611,7 +611,7 @@
 # SMTP_AUTH_MECHANISM=
 
 ## Server name sent during the SMTP HELO
-## By default this value should be is on the machine's hostname,
+## By default this value should be the machine's hostname,
 ## but might need to be changed in case it trips some anti-spam filters
 # HELO_NAME=
 

src/config.rs

@@ -776,7 +776,7 @@ make_config! {
         smtp_auth_mechanism:           String, true,   option;
         /// SMTP connection timeout |> Number of seconds when to stop trying to connect to the SMTP server
         smtp_timeout:                  u64,    true,   def,     15;
-        /// Server name sent during HELO |> By default this value should be is on the machine's hostname, but might need to be changed in case it trips some anti-spam filters
+        /// Server name sent during HELO |> By default this value should be the machine's hostname, but might need to be changed in case it trips some anti-spam filters
         helo_name:                     String, true,   option;
         /// Embed images as email attachments.
         smtp_embed_images:             bool, true, def, true;