Replace all phurl.io short URIs with target URIs

Summary:
As of February 2024, phurl.io (which is not run by Phorge.it) shows HTTP 503 errors instead of redirecting to the target URIs.

Thus replace any URIs pointing to phurl.io with the corresponding target URIs, based on the mapping listed on https://secure.phabricator.com/phurl/.

Closes T15746

Test Plan: Carefully read the diff.

Reviewers: O1 Blessed Committers, valerio.bozzolan

Reviewed By: O1 Blessed Committers, valerio.bozzolan

Subscribers: tobiaswiese, valerio.bozzolan, Matthew, Cigaryno

Maniphest Tasks: T15746

Differential Revision: https://we.phorge.it/D25542

src/init/lib/PhutilMissingSymbolException.php

@@ -18,7 +18,8 @@ final class PhutilMissingSymbolException extends Exception {
       'moved, your library map may need to be rebuilt. You can rebuild '.
       'the map by running "arc liberate".'.
       "\n\n".
-      'For more information, see: https://phurl.io/u/newclasses',
+      'For more information, see: '.
+      'https://we.phorge.it/book/contrib/article/adding_new_classes/',
       $symbol,
       $type,
       $reason);

src/runtime/ArcanistRuntime.php

@@ -188,7 +188,7 @@ final class ArcanistRuntime {
         tsprintf(
           '%s <__%s__>',
           pht('Learn More:'),
-          'https://phurl.io/u/noninteractive'));
+          'https://secure.phabricator.com/T13491'));
 
       throw new PhutilArgumentUsageException(
         pht('Missing required "--" in argument list.'));