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.

admin/tool/task/lib.php

@@ -29,7 +29,7 @@ defined('MOODLE_INTERNAL') || die();
  *
  * @return array of check objects
  */
-function tool_task_status_checks() : array {
+function tool_task_status_checks(): array {
     return [
         new \tool_task\check\cronrunning(),
         new \tool_task\check\maxfaildelay(),