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.

mod/folder/classes/analytics/indicator/cognitive_depth.php

@@ -42,7 +42,7 @@ class cognitive_depth extends activity_base {
      *
      * @return \lang_string
      */
-    public static function get_name() : \lang_string {
+    public static function get_name(): \lang_string {
         return new \lang_string('indicator:cognitivedepth', 'mod_folder');
     }
 

mod/folder/classes/analytics/indicator/social_breadth.php

@@ -42,7 +42,7 @@ class social_breadth extends activity_base {
      *
      * @return \lang_string
      */
-    public static function get_name() : \lang_string {
+    public static function get_name(): \lang_string {
         return new \lang_string('indicator:socialbreadth', 'mod_folder');
     }
 

mod/folder/classes/privacy/provider.php

@@ -38,7 +38,7 @@ class provider implements \core_privacy\local\metadata\null_provider {
      *
      * @return  string
      */
-    public static function get_reason() : string {
+    public static function get_reason(): string {
         return 'privacy:metadata';
     }
 }

mod/folder/lib.php

@@ -848,7 +848,7 @@ function mod_folder_core_calendar_provide_event_action(calendar_event $event,
  * @param  array  $args The path (the part after the filearea and before the filename).
  * @return array The itemid and the filepath inside the $args path, for the defined filearea.
  */
-function mod_folder_get_path_from_pluginfile(string $filearea, array $args) : array {
+function mod_folder_get_path_from_pluginfile(string $filearea, array $args): array {
     // Folder never has an itemid (the number represents the revision but it's not stored in database).
     array_shift($args);