fix(day3): lena better char function

src/day3/main.rs

@@ -25,7 +25,7 @@ trait SymbolCheckable {
 
 impl SymbolCheckable for char {
     fn is_symbol(&self) -> bool {
-        !self.is_alphanumeric() && *self != '.'
+        !self.is_ascii_punctuation() && *self != '.'
     }
 }