docs: replace mixed type of CLI class.

Author: ping-yee

system/CLI/BaseCommand.php

@@ -105,7 +105,7 @@ abstract public function run(array $params);
     /**
      * Can be used by a command to run other commands.
      *
-     * @return mixed
+     * @return int|void
      *
      * @throws ReflectionException
      */
@@ -205,7 +205,7 @@ public function getPad(array $array, int $pad): int
     /**
      * Makes it simple to access our protected properties.
      *
-     * @return mixed
+     * @return array|Commands|LoggerInterface|string|null
      */
     public function __get(string $key)
     {

system/CLI/CLI.php

@@ -915,7 +915,7 @@ public static function getURI(): string
      *
      * **IMPORTANT:** The index here is one-based instead of zero-based.
      *
-     * @return mixed
+     * @return array|string|null
      */
     public static function getSegment(int $index)
     {