flutter_desktop: pin menubar, rotate icon

Signed-off-by: fufesou <shuanglongchen@yeah.net>

src/lang/pl.rs

@@ -343,5 +343,6 @@ pub static ref T: std::collections::HashMap<&'static str, &'static str> =
         ("Network", ""),
         ("Enable RDP", ""),
         ("Pin menubar", "Przypnij pasek menu"),
+        ("Unpin menubar", "Odepnij pasek menu"),
     ].iter().cloned().collect();
 }