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.

lib/phpunit/classes/coverage_info.php

@@ -42,7 +42,7 @@ class phpunit_coverage_info {
      * @param   string  $plugindir The root of the plugin, relative to the dataroot.
      * @return  array
      */
-    final public function get_includelists(string $plugindir) : array {
+    final public function get_includelists(string $plugindir): array {
         $coverages = [];
 
         $includelistfolders = array_merge([
@@ -79,7 +79,7 @@ class phpunit_coverage_info {
      * @param   string  $plugindir The root of the plugin, relative to the dataroot.
      * @return  array
      */
-    final public function get_excludelists(string $plugindir) : array {
+    final public function get_excludelists(string $plugindir): array {
         $coverages = [];
 
         if (!empty($plugindir)) {

lib/phpunit/classes/util.php

@@ -984,7 +984,7 @@ class phpunit_util extends testing_util {
      * @param   int     $level The number of levels of indentation to pad
      * @return  string
      */
-    protected static function pad(string $string, int $level) : string {
+    protected static function pad(string $string, int $level): string {
         return str_repeat(" ", $level * 2) . "{$string}\n";
     }
 
@@ -995,7 +995,7 @@ class phpunit_util extends testing_util {
      * @param   string[] $excludelists The list of files/folders in the excludelist.
      * @return  string
      */
-    protected static function get_coverage_config(array $includelists, array $excludelists) : string {
+    protected static function get_coverage_config(array $includelists, array $excludelists): string {
         $coverages = '';
         if (!empty($includelists)) {
             $coverages .= self::pad("<include>", 2);