feat: prettyify scientific notation

this way it's also typst-compatible!

src/formatting.rs

@@ -34,7 +34,8 @@ pub fn pretty_eval(mut input: String) -> Result<String, Error> {
             ""
         },
         if should_add_back_backslash { " \\" } else { "" }
-    ))
+    )
+    .replace('e', " * 10^"))
 }
 #[test]
 fn test_character_readdition() {