PhabricatorPhabricatorAuthProvider: Remove unnecessary Remarkup

Summary:
This is a small fix in a specific user message example. See other messages in the very same file which also use `<tt>`.

Here the problematic phrase:

{F292970}

See the example in the phrase "Use lowercase letters, digits, and periods. For example: ...".

Test Plan: After this change, the specific message "The URI where the OAuth server is installed. For example" from the page `/auth/config/edit/?provider=PhabricatorPhabricatorAuthProvider` does not have anymore backticks shown to the end user.

Reviewers: O1 Blessed Committers, valerio.bozzolan

Reviewed By: O1 Blessed Committers, valerio.bozzolan

Subscribers: speck, tobiaswiese, valerio.bozzolan, Matthew, Cigaryno

Differential Revision: https://we.phorge.it/D25232

src/applications/auth/provider/PhabricatorPhabricatorAuthProvider.php

@@ -169,7 +169,7 @@ final class PhabricatorPhabricatorAuthProvider
             phutil_tag(
               'tt',
               array(),
-              '`example.oauthserver`'))));
+              'example.oauthserver'))));
     } else {
       $form
         ->appendChild(