fix hex chapter

README.md

@@ -264,7 +264,7 @@ This architecture was something that made intuitive sense at first, but every ti
 
 > Do not add layers of abstractions for the sake of an architecture. Add them whenever you need an extension point that is justified for practical reasons. **[Layers of abstraction aren't free of charge](https://blog.jooq.org/why-you-should-not-implement-layered-architecture), they are to be held in our working memory**.  
 
-If you think that such architectures allow you to quickly swap out different databases or whatever other dependencies you have, you haven't touched the reality. Changing the storage causes lots of issues, and believe us, having the right abstractions for the data access layer is the least of your worries. At best, abstractions can save somewhat 10% of your time (if any), the real pain is in data incompatibilities, communication protocols and [implicit interfaces](https://www.hyrumslaw.com/). So, why pay the price of high cognitive load for such architecture, if it doesn't pay off in the future? Plus, in most cases that future of replacing some core component never happens.  
+If you think that such architectures allow you to quickly swap out different databases or whatever other dependencies, you haven't touched the reality. Changing the storage causes lots of issues, and believe us, having the right abstractions for the data access layer is the least of your worries. At best, abstractions can save somewhat 10% of your time (if any), the real pain is in data incompatibilities, communication protocols and [implicit interfaces](https://www.hyrumslaw.com/). So, why pay the price of high cognitive load for such architecture, if it doesn't pay off in the future? Plus, in most cases that future of replacing some core component never happens.  
 
 Even though these layered architectures have accelerated an important shift from traditional database-centric applications to a somewhat infrastructure-independent approach, where the core business logic is independent of anything external, the idea is by no means novel.