print solve config to stderr

src/main.rs

@@ -12,7 +12,7 @@ mod letterset;
 
 fn main() {
     let cfg = SolveConfig::parse();
-    println!("{cfg:#?}");
+    eprintln!("{cfg:#?}");
 
     let mut dictionary: Vec<_> = BufReader::new(io::stdin().lock())
         .lines()
@@ -39,7 +39,8 @@ fn main() {
 struct SolveConfig {
     /// The maximum length of a solution.
     ///
-    /// Smaller lengths are more likely to fail, but may be faster. Should be >=26.
+    /// Smaller lengths are more likely to fail and make things slower, but they improve the result.
+    /// Should be >=26.
     #[arg(short, long, default_value_t = 30)]
     max_length: u8,