zh_CN: .po refresh and remaining course intro translations

[henrif75]

Normalizes .po file and add professional translation to missing entries before day 1.
#324

[henrif75]

There are fuzzy entries that can be checked after this is merged.

[henrif75]

Thank you @kongy!

[mgeisler]

Hi @henrif75 and @kongy, I think something went wrong here since a lot of translated messages disappeared. Compare these two test runs:

• 1a1a9c8, immediately before this PR: 1387 translated messages, 32 fuzzy translations, 972 untranslated messages.
• 86cde61, part of his PR: 325 translated messages, 18 fuzzy translations, 4 untranslated messages.

I tried checking out 1a1a9c8 and ran msgmerge --update. There are still 1187 translated messages after this, so the problem is not simply that lots of stuff changes in the English version.

Please take the old zh-CN.po file and combine it with the current version using msgcat and then run msgmerge on the result. That should help restore the old translations that still work.

[henrif75]

I agree, it's weird. I guess there was too many PRs at different baselines. I'm going to pull out the open zh-CN PRs and re-merge the translated entries.

[mgeisler]

I agree, it's weird. I guess there was too many PRs at different baselines. I'm going to pull out the open zh-CN PRs and re-merge the translated entries.

Okay, let me know if you run into problems! A quick

msgfmt -o /dev/null --statistics po/zh-CN.po

should tell you the state of the file after the surgery 🙂