Misc quality fixes

[fonskip]

This is just a suggestion, your app, your choices !

Quality fixes based on cargo clippy -- -D clippy::pedantic :

• in src/main.rs
  • no wildcard imports (https://rust-lang.github.io/rust-clippy/master/index.html#/wildcard_imports?groups=pedantic)
  • file extension check made case insensitive using std::path::Path (https://rust-lang.github.io/rust-clippy/master/index.html#/clippy::case_sensitive_file_extension_comparisons?groups=pedantic)
  • added ; at the end of functions that return nothing (https://rust-lang.github.io/rust-clippy/master/index.html#/clippy::semicolon_if_nothing_returned?groups=pedantic)
  • avoid casting from usize (from enumerate()) to u32 by replacing enumerate() with zip(1u32..) (https://rust-lang.github.io/rust-clippy/master/index.html#/cast_possible_truncation?groups=pedantic)
  • match arm that can be replaced by if ….is_ok() (https://rust-lang.github.io/rust-clippy/master/index.html#/single_match_else?groups=pedantic and https://rust-lang.github.io/rust-clippy/master/index.html#/manual_assert?groups=pedantic)
• in src/utils.rs
  • no wildcard imports (see above)
  • quoting of some items in the docstrings with `…`
  • replaced String::from("") with String::new() (https://rust-lang.github.io/rust-clippy/master/index.html#/string::ne?groups=pedantic)
  • put some variables inside of format! strings (https://rust-lang.github.io/rust-clippy/master/index.html#/uninlined_format_args?groups=pedantic)
• in src/distrobox_handler.rs
  • replaced basic closures with the functions themselves (https://rust-lang.github.io/rust-clippy/master/index.html#/redundant_closure_for_method_calls?groups=pedantic)
  • replaced var.iter() with &var when possible (https://rust-lang.github.io/rust-clippy/master/index.html#/explicit_iter_loop?groups=pedantic)
  • put some variables inside of format! strings (see above)
  • replaced String::from("") with String::new() (see above)

Also :

• Passing arguments by reference instead of value (https://rust-lang.github.io/rust-clippy/master/index.html#/needless_pass_by_value). Required some refactor.
• Use --long instead of -l for bash arguments. Increases readability in scripts (https://bertvv.github.io/cheat-sheets/Bash.html)
• Created a bash script to update translations automatically based on a new potfile (similar to what poedit does when you click "tranlation -> update from pot file"). Added corresponding entry in the Makefile (make update-translations)
• Updated translations with the new script

[Dvlv]

Thanks!