cat(1): fixed files not reading to output

src/cat.rs

@@ -62,7 +62,7 @@ fn main() -> ExitCode {
       }
     } else {
       match read_to_string(&path) {
-        Ok(output) => {},
+        Ok(contents) => { output.push_str(&contents) },
         Err(_) => {
           eprintln!("{}: {}: No such file or directory.", &argv0, &path);
           return ExitCode::NoInput;