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.

cache/classes/factory.php

@@ -652,7 +652,7 @@ class cache_factory {
      *
      * @return core_cache\administration_helper
      */
-    public static function get_administration_display_helper() : core_cache\administration_helper {
+    public static function get_administration_display_helper(): core_cache\administration_helper {
         if (is_null(self::$displayhelper)) {
             self::$displayhelper = new \core_cache\local\administration_display_helper();
         }