mention that latter sections should be retained

Author: nikomatsakis

.github/ISSUE_TEMPLATE/meeting-proposal.md

@@ -16,8 +16,8 @@ replace the parenthesized text below as appropriate. We'll discuss
 your proposal in the next planning meeting! (And please do feel free
 to attend!)  Thanks <3.
 
-Oh, and delete this section before you open the issue, if you don't
-mind. :)
+Oh, and please delete this section before you open the issue -- but
+keep the others!
 
 # Meeting proposal info