Update Mail phpdoc (#46173)

Author: bytestream

src/Illuminate/Mail/Message.php

@@ -315,7 +315,7 @@ public function attach($file, array $options = [])
     /**
      * Attach in-memory data as an attachment.
      *
-     * @param  string  $data
+     * @param  string|resource  $data
      * @param  string  $name
      * @param  array  $options
      * @return $this
@@ -366,7 +366,7 @@ function ($data) use ($file) {
     /**
      * Embed in-memory data in the message and get the CID.
      *
-     * @param  string  $data
+     * @param  string|resource  $data
      * @param  string  $name
      * @param  string|null  $contentType
      * @return string