[credits] Add notes for the Polish translation (also: simplify notes taking in info.json)

This reflect the information transmited in
ref: #160 (comment 744468)
by @WorkingWarrior about the previous translation effort; even refactored
it still deserve a note about the first attempt.

I tried to wrap my head around the note taking system in info.json template
with text and author; it is a nice system but a bit too complex for just
adding a general note about the translation. I added a simple node in [credit]
named [notes] where paragraph (ideally short lines) can be added to describe
more accurately the big changes in the history of translation. This case is typical:
a rewrite from scratch; and a attribution for the previous effort.

TODO: makes the credit generator + the big table display this notes.
4 jobs for master in 2 minutes and 7 seconds (queued for 2 seconds)
Name Stage Failure
failed
transcripts Test1
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Found 2 error(s)
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Uploading artifacts for failed job
Uploading artifacts...
ep*/lang/*/*.md: found 248 matching files and directories

WARNING: new-ep*/lang/*/*.md: no matching files
Uploading artifacts as "archive" to coordinator... ok
id=1064172 responseStatus=201 Created token=QTWAZxzo
ERROR: Job failed: exit code 1
failed
status Test2
 M ep32_The-Battlefield/lang/fr/ep32_fr_transcript.md
M ep33_Spell-of-War/lang/pt/ep33_pt_transcript.md
M ep33_Spell-of-War/lang/ro/ep33_ro_transcript.md
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Some files need updating!
You can update all transcripts by running
0_transcripts/validate-transcripts.sh
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ERROR: Job failed: exit code 1