design: fix wording of CoC scope

Update golang/go#13073

Change-Id: I7fc75e033b1c97959cc07a5badb5331b4ffd10ca
Reviewed-on: https://go-review.googlesource.com/17024
Reviewed-by: Andrew Gerrand <adg@golang.org>
diff --git a/design/13073-code-of-conduct.md b/design/13073-code-of-conduct.md
index 103785c..b1f5e02 100644
--- a/design/13073-code-of-conduct.md
+++ b/design/13073-code-of-conduct.md
@@ -70,10 +70,10 @@
 
 #### Where does the Code of Conduct apply?
 
-The Code of Conduct applies generally. If you participate in or contribute to
-the Go ecosystem in any way, you are expected to follow the Code of Conduct.
+If you participate in or contribute to the Go ecosystem in any way,
+you are encouraged to follow the Code of Conduct while doing so.
 
-Explicit enforcement of the Code of Conduct can only practically apply to the
+Explicit enforcement of the Code of Conduct applies to the
 official forums operated by the Go project (“Go spaces”):
 - The official Go GitHub projects,
 - Go project code reviews,