Fix typos in spaces

Fix typo to fit the context

Fix typo add space

Fix small typo

Fix small typo

Fix typo

Fix typo

Fix typo

Fix typo

Fix typo

Fix typo

Fix typo

Update tail.md

Fix typo

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Fix typo

Fix typo

Fix typo

Fix typo

Fix small typo

Fix typo

Fix small typo

Fix typo

Fix typo

Fix typo

Fix typo

Fix typo

Fix typo

Fix typo

Fix typo

Fix typo

snippets/collatz.md

@@ -2,7 +2,7 @@
 
 Applies the Collatz algorithm.
 
-If `n` is even, return `n/2`. Otherwise  return `3n+1`.
+If `n` is even, return `n/2`. Otherwise, return `3n+1`.
 
 ```js
 const collatz = n => (n % 2 == 0) ? (n / 2) : (3 * n + 1);