Set "Zzz " as universal var instead of SleepingSimpleString "translatable" string

[ia]

• Please check if the PR fulfills these requirements

• The changes have been tested locally
• There are no breaking changes

• What kind of change does this PR introduce?
  Localization of SleepingSimpleString in Translations.

Set "Zzz " as universal var instead of SleepingSimpleString "translatable" string.

• What is the current behavior?
  Translation_LANG.json files has SleepingSimpleString set as Zzz universal string.

• What is the new behavior (if this is a feature change)?
  - for EN, traditional Zzz ;
  - for languages, where local version have been added before and if it fits to 3 chars + space, then revert it;
  - for other cases set it as SLP as more international (than Zzz, in my opinion), and as indication that it's not localized [yet].

Remove SleepingSimpleString from Translation_LANG.json files to avoid temptation for further localization.

• Other information:
  Not a big deal but decided to give a second chance to localization of SleepingSimpleString, because I think that it's even funny that there may be "local flavor" in that, so to speak. Let me know what you think. :)

Related PRs/commits in the past:

• Translations/: set Zzzz as SleepingSimpleString in all translations for unification #1866
• Translations/: set "Zzz " as SleepingSimpleString in all translations & revert maxLen value #1869

[discip]

Since I was requested to have a look, here are my 2 cents:

In my opinion, Zzz is easier overall since everyone (At least out of those who will operate a soldering device.😊) knows what it stands for as opposed to SLP.

I just asked some colleagues (native Germans) what they would prefer and they unanimously chose Zzz.

@ia
I hope you don't mind, but my suggestion is to leave it as is. 😅

[ia]

Since I was requested to have a look, here are my 2 cents:

In my opinion, Zzz is easier overall since everyone (At least out of those who will operate a soldering device.😊) knows what it stands for as opposed to SLP.

Note taken. I just remember how even some old portable CD players and digital stereo systems had something like "slp" on their tiny LCD.

I just asked some colleagues (native Germans) what they would prefer and they unanimously chose Zzz.

Aha! Thanks for this servey, really. Good to know for the future. :)

@ia
I hope you don't mind, but my suggestion is to leave it as is. 😅

Well, I have a plan B even for this suggestion. ;)
Will update it here as soon as I back to PC.

[ia]

Here you go. So, in case if the final decision is not to localize SleepingSimpleString ever again at all, then let's just remove it from translation files. In fact, I had this suggestion as the original one. But then I decided to give a second chance for localization. However, since it didn't work out, then how about this suggestion. Let me know what you think. I also updated PR form.

P.S. Dear @discip, I will be very grateful if you will give it brief tests on the real other devices like Pinecil and/or TS101/S60(P). Thanks in advance. Much appreciated.

[discip]

Successfully tested on TS80P, Pinecil 2 & S60P.