MDL-83443 enrol: use defined role name in welcome message.

enrol/manual/tests/behat/welcomemessage.feature

@@ -109,7 +109,7 @@ Feature: A course welcome message will be sent to the user when they are enrolle
     And I should see "Your email address: first@example.com"
     And I should see "Your first name: First"
     And I should see "Your last name: User"
-    And I should see "Your course role: student"
+    And I should see "Your course role: Student"
     # Login as second user and check the notification.
     When I am on the "C1" "course" page logged in as user2
     Then I should see "1" in the "#nav-notification-popover-container [data-region='count-container']" "css_element"
@@ -120,4 +120,4 @@ Feature: A course welcome message will be sent to the user when they are enrolle
     And I should see "Your email address: second@example.com"
     And I should see "Your first name: Second"
     And I should see "Your last name: User"
-    And I should see "Your course role: student"
+    And I should see "Your course role: Student"

enrol/self/tests/behat/welcomemessage.feature

@@ -99,7 +99,7 @@ Feature: A course welcome message will be sent to the user when they auto-enrol
     And I should see "Your email address: first@example.com"
     And I should see "Your first name: First"
     And I should see "Your last name: User"
-    And I should see "Your course role: student"
+    And I should see "Your course role: Student"
     # Login as second user and check the notification.
     And I log in as "user2"
     And I am on "Course 1" course homepage
@@ -112,4 +112,4 @@ Feature: A course welcome message will be sent to the user when they auto-enrol
     And I should see "Your email address: second@example.com"
     And I should see "Your first name: Second"
     And I should see "Your last name: User"
-    And I should see "Your course role: student"
+    And I should see "Your course role: Student"

lib/enrollib.php

@@ -3655,11 +3655,7 @@ abstract class enrol_plugin {
         $context = context_course::instance($instance->courseid);
         $user = core_user::get_user($userid);
         $course = get_course($instance->courseid);
-        $courserole = $DB->get_field(
-            table: 'role',
-            return: 'shortname',
-            conditions: ['id' => $instance->roleid],
-        );
+        $courserole = $DB->get_record('role', ['id' => $instance->roleid]);
 
         $a = new stdClass();
         $a->coursename = format_string($course->fullname, true, ['context' => $context, 'escape' => false]);
@@ -3689,7 +3685,7 @@ abstract class enrol_plugin {
                 $user->email,
                 $user->firstname,
                 $user->lastname,
-                $courserole,
+                role_get_name($courserole, $context),
             ];
             $message = str_replace($placeholders, $values, $message);
             if (strpos($message, '<') === false) {