Alter regex to match different icon styles (resolve #7)

filter.php

@@ -44,7 +44,7 @@ class filter_fontawesome extends moodle_text_filter {
     public function filter($text, array $options = array()) {
 
         // We should search only for reference to FontAwesome icons and if optional icon and fab classes are set.
-        $search = "(\[((?:icon\s)?)((?:fab\s)?)(fa-[a-z0-9 -]+)\])is";
+        $search = "(\[((?:icon\s)?)((?:fa[a-z]\s)?)(fa-[a-z0-9 -]+)\])is";
         $result = preg_replace_callback($search, array($this, 'filter_fontawesome_callback'), $text);
 
         return $result;

tests/filter_test.php

@@ -80,6 +80,10 @@ public function test_cases() {
         $this->run_with_content('icon fa-check fa-4x', true);
         $this->run_with_content('fab fa-telegram', true);
         $this->run_with_content('fab fa-telegram fa-5x', true);
+        $this->run_with_content('fad fa-angel', true);
+        $this->run_with_content('fal fa-child fa-2x', true);
+        $this->run_with_content('fas fa-smile', true);
+        $this->run_with_content('far fa-book', true);
         // Now test some cases that shouldn't be executed.
         $this->run_with_content('Some text fa-check', false);
         $this->run_with_content('fas-check', false);
@@ -89,5 +93,6 @@ public function test_cases() {
         $this->run_with_content('f-check', false);
         $this->run_with_content('fa-check onmouseover="alert(1)"', false);
         $this->run_with_content('fa-check" onmouseover="alert(1)""', false);
+        $this->run_with_content('fad-angel', false);
     }
 }