Get the set of unique characters used in a body of text
For example:
aaaaabbcde 122222222233340
⬇️ ⬇️ ⬇️
abcde 12340
Replace new lines with ", " (comma and space)
For example:
Afghanistan Albania Algeria Andorra Angola
⬇️ ⬇️ ⬇️
Afghanistan, Albania, Algeria, Andorra, Angola