Fix contact/enroll confirmation being hidden along with the form it lived inside

Both forms nested their status message as a child of the <form>, so
form.hidden = true on success hid the confirmation right along with it —
looked like nothing happened. Contact form now resets and stays usable
(you can send another message) instead of disappearing; enroll form still
hides after signup (no reason to sign up twice), but its confirmation is
now a sibling so it actually stays visible.

Also generalized the privacy policy's language from being anchored on
email courses specifically to covering any use of the site.

layouts/_default/contact.html

@@ -18,8 +18,8 @@
   </div>
 
   <button type="submit" class="btn">Send message</button>
-  <p id="contact-status" role="status" style="margin-top:1rem;"></p>
 </form>
+<p id="contact-status" role="status" style="margin-top:1rem;"></p>
 
 <script>
   (function () {
@@ -43,7 +43,7 @@
       }).then(function (res) {
         if (!res.ok) throw new Error("request failed");
         form.reset();
-        form.hidden = true;
+        submitBtn.disabled = false;
         status.textContent = "Thanks — I'll get back to you soon.";
       }).catch(function () {
         submitBtn.disabled = false;