fix the significant_drop_in_scrutinee clippy warning

src/uu/factor/src/cli.rs

@@ -61,8 +61,8 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
         }
     } else {
         let stdin = stdin();
-
-        for line in stdin.lock().lines() {
+        let lines = stdin.lock().lines();
+        for line in lines {
             for number in line.unwrap().split_whitespace() {
                 if let Err(e) = print_factors_str(number, &mut w, &mut factors_buffer) {
                     show_warning!("{}: {}", number.maybe_quote(), e);

src/uu/rm/src/rm.rs

@@ -429,8 +429,8 @@ fn prompt(msg: &str) -> bool {
     let mut buf = Vec::new();
     let stdin = stdin();
     let mut stdin = stdin.lock();
-
-    match stdin.read_until(b'\n', &mut buf) {
+    let read = stdin.read_until(b'\n', &mut buf);
+    match read {
         Ok(x) if x > 0 => matches!(buf[0], b'y' | b'Y'),
         _ => false,
     }

src/uu/wc/src/wc.rs

@@ -474,7 +474,8 @@ fn word_count_from_input(input: &Input, settings: &Settings) -> CountResult {
         Input::Stdin(_) => {
             let stdin = io::stdin();
             let stdin_lock = stdin.lock();
-            match word_count_from_reader(stdin_lock, settings) {
+            let count = word_count_from_reader(stdin_lock, settings);
+            match count {
                 (total, Some(error)) => CountResult::Interrupted(total, error),
                 (total, None) => CountResult::Success(total),
             }