Merge pull request nestjs#2868 from alouini333/hotfix/docs_fix_wording

docs(pipes): update wording

Author: kamilmysliwiec

content/pipes.md

@@ -218,7 +218,7 @@ export class CreateCatDto {
 }
 ```
 
-We want to ensure that any incoming request to the create method contains a valid body. So we have to validate the three members of the `createCatDto` object. We could do this inside the route handler method, but doing so is not ideal as it would break the **single responsibility rule** (SRP).
+We want to ensure that any incoming request to the create method contains a valid body. So we have to validate the three members of the `createCatDto` object. We could do this inside the route handler method, but doing so is not ideal as it would break the **single responsibility principle** (SRP).
 
 Another approach could be to create a **validator class** and delegate the task there. This has the disadvantage that we would have to remember to call this validator at the beginning of each method.