Fix stack overflow when searching in a book with a large TOC

[vitaliynester]

Hello!
When working with a book that has a large table of contents (I attach an example file below), a problem arises with the search. When you try to enter a search query that is not present in the book, the application crashes. I fixed this by rewriting the search function from recursive to a while loop. In my case, this solution helped solve the problem.
The attached epub file has been archived because .epub is not available for attachment: epub file

[vitaliynester]

This fix targets version 2.7.2

[mickael-menu]

Thanks for spotting and fixing this issue @vitaliynester!

Although the main branch is frozen for changes now, would you mind opening a PR targeting develop?

[vitaliynester]

Changed to develop

[mickael-menu]

@vitaliynester I adapted your changes to the latest develop. But as I couldn't reproduce the issue with the book you shared, would you mind checking my changes before I merge it? Thanks.

[vitaliynester]

@vitaliynester I adapted your changes to the latest develop. But as I couldn't reproduce the issue with the book you shared, would you mind checking my changes before I merge it? Thanks.

I apologize for the long response. Yes, after these changes the search works without errors. This is great!