use 'char' instead of 'str' for single character patterns

src/uu/pinky/src/pinky.rs

@@ -275,7 +275,7 @@ impl Pinky {
                 if let Some(n) = gecos.find(',') {
                     gecos.truncate(n + 1);
                 }
-                print!(" {:<19.19}", gecos.replace("&", &pw.name.capitalize()));
+                print!(" {:<19.19}", gecos.replace('&', &pw.name.capitalize()));
             } else {
                 print!(" {:19}", "        ???");
             }
@@ -339,7 +339,7 @@ impl Pinky {
         for u in &self.names {
             print!("Login name: {:<28}In real life: ", u);
             if let Ok(pw) = Passwd::locate(u.as_str()) {
-                println!(" {}", pw.user_info.replace("&", &pw.name.capitalize()));
+                println!(" {}", pw.user_info.replace('&', &pw.name.capitalize()));
                 if self.include_home_and_shell {
                     print!("Directory: {:<29}", pw.user_dir);
                     println!("Shell:  {}", pw.user_shell);

src/uucore/src/lib/features/fs.rs

@@ -505,7 +505,7 @@ mod tests {
             let normalized = normalize_path(path);
             assert_eq!(
                 test.test
-                    .replace("/", std::path::MAIN_SEPARATOR.to_string().as_str()),
+                    .replace('/', std::path::MAIN_SEPARATOR.to_string().as_str()),
                 normalized.to_str().expect("Path is not valid utf-8!")
             );
         }

tests/by-util/test_pinky.rs

@@ -24,7 +24,7 @@ fn test_capitalize() {
 fn test_long_format() {
     let login = "root";
     let pw: Passwd = Passwd::locate(login).unwrap();
-    let real_name = pw.user_info.replace("&", &pw.name.capitalize());
+    let real_name = pw.user_info.replace('&', &pw.name.capitalize());
     let ts = TestScenario::new(util_name!());
     ts.ucmd().arg("-l").arg(login).succeeds().stdout_is(format!(
         "Login name: {:<28}In real life:  {}\nDirectory: {:<29}Shell:  {}\n\n",