Add 'Changes' line to issue list template

Author: fantasai

bin/issuegen.pl

@@ -34,6 +34,7 @@
 From:     [name]
 Comment:  [url]
 Response: [url]
+Changes:  [changeset(s) or new section or left blank for “It's complicated.” ]
 Closed:   Accepted/OutOfScope/Invalid/Rejected/Retracted/Deferred ... or replace this line with "Open"
 Verified: [url]
 Resolved: Editorial/Bugfix (for obvious fixes)/Editor discretion/[url to minutes]
@@ -84,6 +85,12 @@
 is to minimize the effort required for someone reviewing the issues
 to understand this issue and its resolution.
 
+Changes:  A reference to the diffs, or equivalently useful information
+          such as a link to the relevant section. Often left blank in
+          early-stage drafts (which have a lot of churn) or when
+          there's a long discussion involving multiple sets of changes
+          and it's therefore easier just to look at the result.
+
 Closed:   A status line on how the issue was closed. Triggers colors.
           Replacing "Closed" with "Open" marks the issue unresolved.