KEP template: move guidance for line breaks

The last three new KEPs that I started to review all didn't use line-wrapping,
including one from an experienced Kubernetes contributor. Apparently we have
to put the existing guidance on line breaks into a more prominent spot.

Author: pohly

keps/NNNN-kep-template/README.md

@@ -1,6 +1,13 @@
 <!--
 **Note:** When your KEP is complete, all of these comment blocks should be removed.
 
+Follow the guidelines of the [documentation style guide].
+In particular, wrap lines to a reasonable length, to make it
+easier for reviewers to cite specific portions, and to minimize diff churn on
+updates.
+
+[documentation style guide]: https://github.com/kubernetes/community/blob/master/contributors/guide/style-guide.md
+
 To get started with this template:
 
 - [ ] **Pick a hosting SIG.**
@@ -164,13 +171,6 @@ should help to ensure that the tone and content of the `Summary` section is
 useful for a wide audience.
 
 A good summary is probably at least a paragraph in length.
-
-Both in this section and below, follow the guidelines of the [documentation
-style guide]. In particular, wrap lines to a reasonable length, to make it
-easier for reviewers to cite specific portions, and to minimize diff churn on
-updates.
-
-[documentation style guide]: https://github.com/kubernetes/community/blob/master/contributors/guide/style-guide.md
 -->
 
 ## Motivation