fix: whatsapp & signal embedding yes, signal uses WhatsApp/2 as user agent

Signed-off-by: rooot <[e-mail]>

src/meow.rs

···
         "TwitterBot",
         "FacebookBot",
         "Conduwuit",
+        "WhatsApp", // this is also signal
         // not a bot but used for debugging :3c
         "curl/",
     ];