fix: psalm errors

src/ChildStderr.php

@@ -6,12 +6,18 @@ namespace Nih\CommandBuilder;
 
 use Override;
 
+/**
+ *
+ */
 final class ChildStderr implements StdioInterface
 {
     use StreamReadTrait;
 
+    /**
+     * @return resource
+     */
     #[Override]
-    public function getDescriptionSpec(int $fd): mixed
+    public function getDescriptiorSpec(int $fd): mixed
     {
         return $this->stream;
     }