refactor: try simplifying the condition logic

crates/fmt/src/formatter.rs

@@ -1640,16 +1640,15 @@ impl<'a, W: Write> Formatter<'a, W> {
                         )?;
                     // Write new line if we have only one parameter and params first set,
                     // or if the function definition is multiline and all params set.
-                    if params.len() == 1 &&
-                        (matches!(
+                    let single_param_multiline = matches!(
+                        fmt.config.multiline_func_header,
+                        MultilineFuncHeaderStyle::ParamsFirst
+                    ) || params_multiline &&
+                        matches!(
                             fmt.config.multiline_func_header,
-                            MultilineFuncHeaderStyle::ParamsFirst
-                        ) || params_multiline &&
-                            matches!(
-                                fmt.config.multiline_func_header,
-                                MultilineFuncHeaderStyle::AllParams
-                            ))
-                    {
+                            MultilineFuncHeaderStyle::AllParams
+                        );
+                    if params.len() == 1 && single_param_multiline {
                         writeln!(fmt.buf())?;
                     }
                     fmt.write_chunks_separated(&params, ",", params_multiline)?;