* Replacing spaces with newlines

From https://database.lichess.org/#puzzles :

#+BEGIN_QUOTE
 % cat lichess_db_puzzle.csv| head
PuzzleId,FEN,Moves,Rating,RatingDeviation,Popularity,NbPlays,Themes,GameUrl,OpeningTags
00008,r6k/pp2r2p/4Rp1Q/3p4/8/1N1P2R1/PqP2bPP/7K b - - 0 24,f2g3 e6e7 b2b1 b3c1 b1c1 h6c1,1900,76,95,8222,crushing hangingPiece long middlegame,https://lichess.org/787zsVup/black#48,
0000D,5rk1/1p3ppp/pq3b2/8/8/1P1Q1N2/P4PPP/3R2K1 w - - 2 27,d3d6 f8d8 d6d8 f6d8,1442,74,96,33118,advantage endgame short,https://lichess.org/F8M8OS71#53,
0008Q,8/4R3/1p2P3/p4r2/P6p/1P3Pk1/4K3/8 w - - 1 64,e7f7 f5e5 e2f1 e5e6,1358,76,91,719,advantage endgame rookEndgame short,https://lichess.org/MQSyb3KW#127,
0009B,r2qr1k1/b1p2ppp/pp4n1/P1P1p3/4P1n1/B2P2Pb/3NBP1P/RN1QR1K1 b - - 1 16,b6c5 e2g4 h3g4 d1g4,1136,74,88,594,advantage middlegame short,https://lichess.org/4MWQCxQ6/black#32,Kings_Pawn_Game Kings_Pawn_Game_Leonardis_Variation

...

 % cat lichess_db_puzzle.csv| cut -d ',' -f8 | head
Themes
crushing hangingPiece long middlegame
advantage endgame short
advantage endgame rookEndgame short
advantage middlegame short
crushing endgame long
crushing endgame long pawnEndgame
...

 % cat lichess_db_puzzle.csv| cut -d ',' -f8 | tr ' ' '\n' | head
Themes
crushing
hangingPiece
long
middlegame
advantage
endgame
short
advantage
endgame
...

 % cat lichess_db_puzzle.csv| cut -d ',' -f8 | tr ' ' '\n' | sort | uniq -c
 315530 advancedPawn
1512381 advantage
   6001 anastasiaMate
   5915 arabianMate
  36398 attackingF2F7
 185468 attraction
...

1546267 mate
 695790 mateIn1
 661310 mateIn2
 160803 mateIn3
  23334 mateIn4
   5030 mateIn5
...
#+END_QUOTE