docs: grammar and wording fixes in active-record-data-mapper.md (typeorm#4615)

Grammar and wording fixes in bottom paragraph

Author: JB Reefer

docs/active-record-data-mapper.md

@@ -185,7 +185,7 @@ Learn more about [custom repositories](custom-repository.md).
 The decision is up to you.
 Both strategies have their own cons and pros.
 
-One thing we should always keep in mind in software development is how we are going to maintain it.
-The `Data Mapper` approach helps you with maintainability of your software which is more effective in bigger apps.
-The `Active record` approach helps you to keep things simple which works good in small apps.
+One thing we should always keep in mind in with software development is how we are going to maintain our applications.
+The `Data Mapper` approach helps with maintainability, which is more effective in bigger apps.
+The `Active record` approach helps keep things simple which works well in smaller apps.
  And simplicity is always a key to better maintainability.