How does "Power over Factorial" imply convergence of $e^x$?

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I was going through the following proof of the fact that $\sum_{n = 0}^\infty x^n/n! = \lim_{n\to\infty}(1 + x/n)^n$ at ProofWiki:

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The Power over Factorial entry states that $x^n/n!\to 0$ for any real $x$.

However, I am at loss on how this helps in concluding that $$ 1 + x + \left( \frac{n - 1}{n} \right)\frac{x^2}{2!} + \cdots $$ goes to the claimed limit $1 + x + x^2/2! + \cdots$.

Any help?