docs: change doc type "mixed" to others type in Rule, Validation, ValidationInterface class

Author: ping-yee

system/Validation/Rules.php

@@ -209,7 +209,7 @@ public function not_in_list(?string $value, string $list): bool
     }
 
     /**
-     * @param mixed $str
+     * @param object|array|string|int|float|null $str
      */
     public function required($str = null): bool
     {

system/Validation/Validation.php

@@ -183,7 +183,7 @@ public function run(?array $data = null, ?string $group = null, ?string $dbGroup
      * Runs the validation process, returning true or false
      * determining whether validation was successful or not.
      *
-     * @param mixed    $value
+     * @param object|array|string|int|float|bool|null $value
      * @param string[] $errors
      */
     public function check($value, string $rule, array $errors = []): bool

system/Validation/ValidationInterface.php

@@ -31,7 +31,7 @@ public function run(?array $data = null, ?string $group = null): bool;
      * Check; runs the validation process, returning true or false
      * determining whether or not validation was successful.
      *
-     * @param mixed    $value  Value to validation.
+     * @param object|array|string|int|float|bool|null $value  Value to validation.
      * @param string   $rule   Rule.
      * @param string[] $errors Errors.
      *