Fixed Bug 1032426 - Unclear that front page displays only some tasks

@glogiotatidis  or @akatsoulas  Please review my PR.https://bugzilla.mozilla.org/show_bug.cgi?id=1032426

Thank you in advance
Your change is OK. You also have the opportunity to make the string localizable. To do so change it to `{{ _('Suggested First Tasks') }}`

Don't forget to `git commit --amend` :)