Extend code review docs with chapter about the right balance

What does this MR do?

This MR extends the code review docs with chapter about the right balance.

doc/development/code_review.md

@@ -87,12 +87,12 @@ reviewee.
   design is important as well. Building abstractions and good design is what
   makes it possible to hide complexity and is a leverage for the future work.
 - Asking reviewee to change the design sometimes means the complete rewrite of
-  the contributed code. It is usually a good idea to ask an other merge request
-  endboss before doing it, but have a courage to do it when you believe it is
+  the contributed code. It is usually a good idea to ask other merge request
+  endboss before doing it, but have the courage to do it when you believe it is
   important.
 - There is a difference in doing things right and doing things right now.
-  Ideally we should do the former but in real world we need the latter as well.
-  The good example is a security fix which should be released as soon as
+  Ideally, we should do the former, but in the real world we need the latter as
+  well. The good example is a security fix which should be released as soon as
   possible. Asking reviewee to do the major refactoring in the merge request
   that is an urgent fix should be avoided.
 - Doing things well today is usually better than doing something perfectly