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.

backup/controller/backup_controller.class.php

@@ -380,7 +380,7 @@ class backup_controller extends base_controller {
      * @return bool
      * @throws dml_exception
      */
-    protected function get_include_files_default() : bool {
+    protected function get_include_files_default(): bool {
         // We normally include files.
         $includefiles = true;