Bug 1527418: Add missing l10n-id to newInstallPage.html. r=Gijs

Differential Revision: https://phabricator.services.mozilla.com/D19561

--HG--
extra : moz-landing-system : lando

browser/base/content/newInstallPage.html

@@ -40,7 +40,7 @@
       <form id="sync">
         <h1 id="sync-header" data-l10n-id="sync-header"></h1>
         <p id="sync-label"><label data-l10n-id="sync-label" for="sync-input"></label></p>
-        <p id="sync-input-container"><input id="sync-input" type="email" required name="email" placeholder="Email"></p>
+        <p id="sync-input-container"><input data-l10n-id="sync-input" id="sync-input" type="email" required name="email"></p>
         <p id="sync-terms" data-l10n-id="sync-terms">
           <a data-l10n-name="terms" href="https://accounts.firefox.com/legal/terms" target="_blank" rel="noopener"></a>
           <a data-l10n-name="privacy" href="https://accounts.firefox.com/legal/privacy" target="_blank" rel="noopener"></a>