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.

auth/none/auth.php

@@ -57,7 +57,7 @@ class auth_plugin_none extends auth_plugin_base {
      * @param string $password The password
      * @return bool Authentication success or failure.
      */
-    function user_login ($username, $password) {
+    function user_login($username, $password) {
         global $CFG, $DB;
         if ($user = $DB->get_record('user', array('username'=>$username, 'mnethostid'=>$CFG->mnet_localhost_id))) {
             return validate_internal_user_password($user, $password);