docs: fix Method-Chaining example results

[kyechan99]

Fix

Modified the example results from /docs/method-chaining.

Before

fx("abc")
  .map((a) => a.toUpperCase()) // ["a", "b"]
  .take(2)
  .toArray(); // ["a", "b"]

After

fx("abc")
  .map((a) => a.toUpperCase()) // ["A", "B"]
  .take(2)
  .toArray(); // ["A", "B"]

[ppeeou]

@kyechan99

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