Clean up comments broken by rustfmt

In c0fbe42 we ran `rustfmt` on
some code in `channel.rs`, which broke some comments which referred
to code on a specific line. Here we fix those comments.

Author: TheBlueMatt

lightning/src/ln/channel.rs

@@ -6024,13 +6024,13 @@ where
 		2*(1 + 71); // two signatures + sighash type flags
 		if let Some(spk) = a_scriptpubkey {
 			ret += ((8+1) +                                    // output values and script length
-				spk.len() as u64)
-				* 4; // scriptpubkey and witness multiplier
+				spk.len() as u64)                              // scriptpubkey
+				* 4; // witness multiplier
 		}
 		if let Some(spk) = b_scriptpubkey {
 			ret += ((8+1) +                                    // output values and script length
-				spk.len() as u64)
-				* 4; // scriptpubkey and witness multiplier
+				spk.len() as u64)                              // scriptpubkey
+				* 4; // witness multiplier
 		}
 		ret
 	}