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.

analytics/classes/model.php

@@ -1597,7 +1597,7 @@ class model {
      * @param bool $includeweights Include the model weights if available
      * @return string Zip file path
      */
-    public function export_model(string $zipfilename, bool $includeweights = true) : string {
+    public function export_model(string $zipfilename, bool $includeweights = true): string {
 
         \core_analytics\manager::check_can_manage_models();
 
@@ -1614,7 +1614,7 @@ class model {
      * @param  string $zipfilepath Zip file path
      * @return \core_analytics\model
      */
-    public static function import_model(string $zipfilepath) : \core_analytics\model {
+    public static function import_model(string $zipfilepath): \core_analytics\model {
 
         \core_analytics\manager::check_can_manage_models();
 
@@ -1627,7 +1627,7 @@ class model {
      *
      * @return bool
      */
-    public function can_export_configuration() : bool {
+    public function can_export_configuration(): bool {
 
         if (empty($this->model->timesplitting)) {
             return false;
@@ -1680,7 +1680,7 @@ class model {
      *
      * @return bool
      */
-    public function trained_locally() : bool {
+    public function trained_locally(): bool {
         global $DB;
 
         if (!$this->is_trained() || $this->is_static()) {