Fix: Various href changes that seem to have applied automatically

Author: markrandall

public/cal.php

@@ -98,7 +98,7 @@
 <div class="tip">
  <p>
   If you would like to suggest an upcoming event to be listed on this
-  calendar, you can use <a href="../submit-event.php">our event submission
+  calendar, you can use <a href="/submit-event.php">our event submission
   form</a>.
  </p>
  <p>

public/docs.php

@@ -65,7 +65,7 @@
 
 <p>
  Information about php.net URL shortcuts can be found by visiting our
- <a href="../urlhowto.php">Navigation tips &amp; tricks page</a>.
+ <a href="/urlhowto.php">Navigation tips &amp; tricks page</a>.
 </p>
 
 <h2 class="content-header">More documentation</h2>

public/downloads.php

@@ -203,7 +203,7 @@ function option(string $value, string $desc, $attributes = []): string
 <?php gpg_key_show_keys(true /* activeOnly */); ?>
 
 <p>
-    <a href="../gpg-keys.php">
+    <a href="/gpg-keys.php">
         A full list of GPG keys used for current and older releases is also
         available.
     </a>