Use f-strings
Avoid unnecessary casts to str()bool()int()
Ensure file closure
Merge nested ifs
Simplify for-assigns-appends with comprehensions and internal functions
Avoid shadowing internal function names
Initialize variables
Return value directly instead of assign then return
Make some methods static
* Added Polish translation
* Updated polish translation, fixed plural forms for "hour" in KlipperScreen.pot
* updated en lang, forgot trailing new line in .pot
* Small updates to .pl language translation
