resolve half of the integer_arithmetic lints, couple misc changes

Signed-off-by: strawberry <strawberry@puppygock.gay>

src/service/sending/send.rs

@@ -818,7 +818,7 @@ impl FedDest {
 	fn into_uri_string(self) -> String {
 		match self {
 			Self::Literal(addr) => addr.to_string(),
-			Self::Named(host, port) => host + &port,
+			Self::Named(host, port) => format!("{host}{port}"),
 		}
 	}