[TASK] Use correct external link RST syntax

Resolves: #100190
Related: #99499
Releases: main
Change-Id: I1148d368a1f961a34311a0d931999eedbbb0317e
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78141


Tested-by: Nikita Hovratov <nikita.h@live.de>
Tested-by: Chris Müller <typo3@krue.ml>
Reviewed-by: Nikita Hovratov <nikita.h@live.de>
Reviewed-by: Chris Müller <typo3@krue.ml>
Reviewed-by: Oliver Hader <oliver.hader@typo3.org>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Hader <oliver.hader@typo3.org>

typo3/sysext/core/Documentation/Changelog/12.3/Feature-99499-IntroduceContent-Security-PolicyHandling.rst

@@ -12,7 +12,7 @@ Description
 ===========
 
 Corresponding representation of the W3C standard of
-`Content-Security-Policy (CSP) <https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy>`
+`Content-Security-Policy (CSP) <https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy>`__
 has been introduced to TYPO3. Content-Security-Policy declarations can either be provided by using the
 the general builder pattern of :php:`\TYPO3\CMS\Core\Security\ContentSecurityPolicy\Policy`, extension
 specific mutations (changes to the general policy) via :file:`Configuration/ContentSecurityPolicies.php`