Update style.css (#5377)

Fixed typo in the theme name to match folder name (Bennett).

bennett/style.css

@@ -1,5 +1,5 @@
 /*
-Theme Name: Bennet
+Theme Name: Bennett
 Theme URI: https://wordpress.com/theme/bennett
 Author: Automattic
 Author URI: https://automattic.com/
@@ -36,4 +36,4 @@ Used in theme screenshot and demo site.
 Still life photo of a kiwi fruit by Michal Jarmoluk
 Source: https://pixabay.com/photos/kiwi-fruit-vitamins-healthy-eating-428080/
 Used in theme demo site.
-*/
+*/