Fix missing type in slide 8

"int" was missing after "x, y"
Update translation of constant slide

등 -> 숫자 타입
Also polish up the translation
Remove duplicate '을' in slide #20 (If)
Translate Exercise 1: Loops and Functions

Add translation and missing image for Newton's method
Translate Exercise 2: Slices

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Translate Exercise 3: Maps

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Translate Exercise 4: Fibonacci closure

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Translate Advanced Exercise: Complex cube roots

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Merge pull request #2 from namhyung/fixes

Translation updates