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.

question/classes/external.php

@@ -223,7 +223,7 @@ class core_question_external extends external_api {
      * @see \qbank_tagquestion\external\qbank_tagquestion_external
      * @todo Final deprecation on Moodle 4.4 MDL-72438
      */
-    public static function  submit_tags_form_returns() {
+    public static function submit_tags_form_returns() {
         return new external_single_structure([
                 'status' => new external_value(PARAM_BOOL, 'status: true if success')
         ]);
@@ -346,7 +346,7 @@ class core_question_external extends external_api {
     /**
      * Returns description of method result value.
      */
-    public static function  get_random_question_summaries_returns() {
+    public static function get_random_question_summaries_returns() {
         return new external_single_structure([
             'totalcount' => new external_value(PARAM_INT, 'total number of questions in result set'),
             'questions' => new external_multiple_structure(

question/classes/local/bank/edit_menu_column.php

@@ -69,7 +69,7 @@ class edit_menu_column extends column_base {
         echo $OUTPUT->render($menu);
     }
 
-    public function get_required_fields():array {
+    public function get_required_fields(): array {
         return ['q.qtype'];
     }
 

question/classes/privacy/provider.php

@@ -73,7 +73,7 @@ class provider implements
      * @param   collection  $items  The collection to add metadata to.
      * @return  collection  The array of metadata
      */
-    public static function get_metadata(collection $items) : collection {
+    public static function get_metadata(collection $items): collection {
         // Other tables link against it.
 
         // The 'question_usages' table does not contain any user data.
@@ -335,7 +335,7 @@ class provider implements
      * @param   int             $userid The user to search.
      * @return  contextlist     $contextlist The contextlist containing the list of contexts used in this plugin.
      */
-    public static function get_contexts_for_userid(int $userid) : contextlist {
+    public static function get_contexts_for_userid(int $userid): contextlist {
         $contextlist = new contextlist();
 
         // A user may have created or updated a question.
@@ -390,7 +390,7 @@ class provider implements
      * @param   int             $userid     The user to search.
      * @return  \qubaid_join
      */
-    public static function get_related_question_usages_for_user(string $prefix, string $component, string $joinfield, int $userid) : \qubaid_join {
+    public static function get_related_question_usages_for_user(string $prefix, string $component, string $joinfield, int $userid): \qubaid_join {
         return new \qubaid_join("
                 JOIN {question_usages} {$prefix}_qu ON {$prefix}_qu.id = {$joinfield}
                  AND {$prefix}_qu.component = :{$prefix}_usagecomponent