web: rename login placeholder for mailbox to email address (#6693)

data/web/lang/lang.de-de.json

@@ -846,7 +846,8 @@
         "password": "Passwort",
         "reset_password": "Passwort zurücksetzen",
         "request_reset_password": "Passwortänderung anfordern",
-        "username": "Benutzername"
+        "username": "Benutzername",
+        "email": "E-Mail-Adresse"
     },
     "mailbox": {
         "action": "Aktion",

data/web/lang/lang.en-gb.json

@@ -847,7 +847,8 @@
         "password": "Password",
         "reset_password": "Reset Password",
         "request_reset_password": "Request password change",
-        "username": "Username"
+        "username": "Username",
+        "email": "Email address"
     },
     "mailbox": {
         "action": "Action",

data/web/templates/user_index.twig

@@ -48,7 +48,7 @@
             <label class="visually-hidden" for="login_user">{{ lang.login.username }}</label>
             <div class="input-group">
               <div class="input-group-text"><i class="bi bi-person-fill"></i></div>
-              <input name="login_user" autocorrect="off" autocapitalize="none" type="{% if is_mobileconfig %}email{% else %}text{% endif %}" id="login_user" class="form-control" placeholder="{{ lang.login.username }}" required="" autofocus="" autocomplete="username">
+              <input name="login_user" autocorrect="off" autocapitalize="none" type="{% if is_mobileconfig %}email{% else %}text{% endif %}" id="login_user" class="form-control" placeholder="{{ lang.login.email }}" required="" autofocus="" autocomplete="username">
             </div>
           </div>
           <div class="d-flex mt-3">