message: Add `src/**/*.rs.bk` to VCS ignore file
  Limit `target` exclusion to `target/` dirs.
diff: @@ -435,19 +435,17 @@ fn mk(config: &Config, opts: &MkOptions) -> CargoResult<()> {
  let path = opts.path;
  let name = opts.name;
  let cfg = global_config(config)?;
  - let mut ignore = "target\n".to_string();
  - let in_existing_vcs_repo = existing_vcs_repo(path.parent().unwrap(), config.cwd());
  - if !opts.bin {
  - ignore.push_str("Cargo.lock\n");
  - }
  + let ignore = ["target/\n", "src/**/*.rs.bk\n",
  + if !opts.bin { "Cargo.lock\n" } else { "" }]
  + .concat();
  + let in_existing_vcs_repo = existing_vcs_repo(path.parent().unwrap(), config.cwd());
  let vcs = match (opts.version_control, cfg.version_control, in_existing_vcs_repo) {
  (None, None, false) => VersionControl::Git,
  (None, Some(option), false) => option,
  (Some(option), _, _) => option,
  (_, _, true) => VersionControl::NoVcs,
  };
  -
  match vcs {
  VersionControl::Git => {
  if !fs::metadata(&path.join(".git")).is_ok() {
  