Add “The Power of Positive Thinking” to the book list

[sarahracaj]

I would like to add the book The Power of Positive Thinking by Norman Vincent Peale to the existing list of books in this repository. The book is widely recognized as an influential classic in the field of self-development and fits the theme and structure of the current list.

I checked the relevance and the details of the book:
• Title: The Power of Positive Thinking
• Author: Norman Vincent Peale
• Published: 1952

I also reviewed the formatting and ordering rules of the current list to make sure the new entry fits in cleanly.
The book is not already included, and adding it doesn’t require any other changes or dependencies.

The contribution is straightforward: simply adding one correctly formatted entry to the appropriate section of the list.