WebUI: allow string to be translated

Closes #17759.

src/webui/www/private/views/preferences.html

@@ -791,7 +791,7 @@
                 <label for="bypass_auth_subnet_whitelist_checkbox">QBT_TR(Bypass authentication for clients in whitelisted IP subnets)QBT_TR[CONTEXT=OptionsDialog]</label>
             </div>
             <div class="formRow" style="padding-left: 30px; padding-top: 5px;">
-                <textarea id="bypass_auth_subnet_whitelist_textarea" rows="5" cols="48" placeholder="Example: 172.17.32.0/24, fdff:ffff:c8::/40"></textarea>
+                <textarea id="bypass_auth_subnet_whitelist_textarea" rows="5" cols="48" placeholder="QBT_TR(Example: 172.17.32.0/24, fdff:ffff:c8::/40)QBT_TR[CONTEXT=OptionsDialog]"></textarea>
             </div>
             <table>
                 <tr>