Update posts/2021/12/error-message-style-guides.txt

Co-authored-by: Matti Picus <matti.picus@gmail.com>

Author: cfbolz

posts/2021/12/error-message-style-guides.txt

@@ -57,7 +57,8 @@ this use case it's important that the message is short. On the other hand, 20%
 of the times this same message will have to be understood by a developer who
 has never seen it before and is confused, and so the message needs to contain
 enough information
-to allow them to find out what is going on.
+to allow them to find out what is going on. So the error message needs to strike
+a balance between brevity and clarity.
 
 The Racket guide proposes to use the following general structure for errors:
 'State the constraint that was violated ("expected a"), followed by what was