design: remove vague clause from compatibility section

Change-Id: I6fc2ebd570be36399e66869160f8bbbea364bcf0
Reviewed-on: https://go-review.googlesource.com/12887
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/design/TEMPLATE.md b/design/TEMPLATE.md
index fb3a013..73802f3 100644
--- a/design/TEMPLATE.md
+++ b/design/TEMPLATE.md
@@ -25,8 +25,7 @@
 ## Compatibility
 
 [A discussion of the change with regard to the
-[compatibility guidelines](https://golang.org/doc/go1compat)
-and future maintainability.]
+[compatibility guidelines](https://golang.org/doc/go1compat).]
 
 ## Implementation