message: refactor: Fix clippy lint for entry vacancy check
diff: //! Process data collection for Linux.
  +use std::collections::hash_map::Entry;
  +
  use crate::utils::error::{self, BottomError};
  use crate::Pid;
  @@ -232,9 +234,9 @@ pub fn get_process_data(
  if let Ok(dir) = dir {
  if let Ok(pid) = dir.file_name().to_string_lossy().trim().parse::<Pid>() {
  let mut fresh = false;
  - if !pid_mapping.contains_key(&pid) {
  + if let Entry::Vacant(entry) = pid_mapping.entry(pid) {
  if let Ok(ppd) = PrevProcDetails::new(pid) {
  - pid_mapping.insert(pid, ppd);
  + entry.insert(ppd);
  fresh = true;
  } else {
  // Bail early.
  