[FEATURE] Add Maltese (mt) as supported language

This change adds support for Maltese to be selected as
TYPO3 Language and to connect to TYPO3 Localizations
(XLF files, Site Configuration) by default.

Maltese language is spoken in Malta.

Also see https://en.wikipedia.org/wiki/Languages_of_Malta

Resolves: #103331
Releases: main
Change-Id: Ib8bb4112f094f9379e8d46c90291b281335ade4d
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/83319
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Marvin Buchmann <marvin_buchmann@web.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Marvin Buchmann <marvin_buchmann@web.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>

typo3/sysext/core/Classes/Localization/Locales.php

@@ -79,6 +79,7 @@ class Locales implements SingletonInterface
         'mi' => 'Maori',
         'mk' => 'Macedonian',
         'ms' => 'Malay',
+        'mt' => 'Maltese',
         'nl' => 'Dutch',
         'no' => 'Norwegian',
         'pl' => 'Polish',

typo3/sysext/core/Documentation/Changelog/13.1/Feature-103331-NativeSupportForLanguageMalteseAdded.rst

@@ -0,0 +1,34 @@
+.. include:: /Includes.rst.txt
+
+.. _feature-103331:
+
+============================================================
+Feature: #103331 - Native support for language Maltese added
+============================================================
+
+See :issue:`103331`
+
+Description
+===========
+
+TYPO3 now supports Maltese. Maltese language is spoken in Malta.
+
+The ISO 639-1 code for Maltese is "mt", which is how TYPO3
+accesses the language internally.
+
+
+Impact
+======
+
+It is now possible to
+
+*  Fetch translated labels from translations.typo3.org / CrowdIn automatically
+   within the TYPO3 Backend
+*  Switch the backend interface to Maltese language
+*  Create a new language in a site configuration using Maltese
+*  Create translation files with the "mt" prefix (such as `mt.locallang.xlf`)
+   to create your own labels
+
+and TYPO3 will pick Maltese as a language just like any other supported language.
+
+.. index:: Backend, Frontend, ext:core