Update how-to-write-your-first-technical-book.md

[Narcissus91]

Checklist:

• [x] I have read freeCodeCamp's contribution guidelines.
• [x] My pull request has a descriptive title (not a vague title like Update index.md)

Closes #1137

[Narcissus91]

@miyaliu666 这篇翻译好了

[miyaliu666]

翻译得非常好，我写了一点点建议，谢谢 @Narcissus91 ！