MDL-65292 style: Fix all function declarations white space

This has been generated running the following Sniffs, all
them part of the Moodle's CodeSniffer standard:
- PSR12.Functions.ReturnTypeDeclaration
- PSR12.Functions.NullableTypeDeclaration
- moodle.Methods.MethodDeclarationSpacing
- Squiz.Whitespace.ScopeKeywordSpacing

All them are, exclusively, about correct spacing, so the changes
are, all them, only white space changes.

Only exceptions to the above are 3 changes what were setting the
return type in a new line, and, when that happens, the closing
parenthesis (bracket) has to go to the same line than the colon.

course/classes/analytics/indicator/completion_enabled.php

@@ -42,7 +42,7 @@ class completion_enabled extends \core_analytics\local\indicator\binary {
      *
      * @return new \lang_string
      */
-    public static function get_name() : \lang_string {
+    public static function get_name(): \lang_string {
         return new \lang_string('indicator:completionenabled', 'moodle');
     }