MDL-75963 filter: Added code highlighter filter

If enabled, the filter will convert text wrapped by language-* style class
into a well-styled block of code.
The filter uses PrismJS, and it also used by the TinyMCE editor to
highlight the code sample plugin.

filter/codehighlighter/amd/src/prism-init.js

@@ -0,0 +1,25 @@
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Prism.js initialization.
+ *
+ * @module     filter/codegihlighter
+ * @copyright  2023 Meirza <meirza.arson@moodle.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+define(['./prism'], function(PrismJS) {
+    PrismJS.highlightAll();
+});