Add tech / halo risk description; Clean up language

.github/pull_request_template.md

@@ -1,15 +1,27 @@
 ### Purpose of this PR
 
-[Desc of feature/change. Links to screenshots, design docs, user docs, etc. Remember reviewers may be outside your team, and not know your feature/area that should be explained more.]
+[Description of the feature/changes. Links to screenshots, design docs, user docs, etc. as necessary. Consider which reviewers may be outside of your team and how much of the feature/area should be explained more.]
 
 ### Testing status
 
-[Explanation of what’s tested, how tested and existing or new automation tests. Can include manual testing by self and/or QA. Specify test plans. Rarely acceptable to have no testing.]
+[Explanation of what’s been tested, how it was tested, and existing or new automation tests. Can include manual testing by self and/or QA. Specify test plans. Rarely acceptable to have no testing.]
 
-### Technical risk
+### Technical / Halo risk
 
-[Overall product level assessment of risk of change. Need technical risk & halo effect.]
+[Overall product level assessment of the risk of the changes using the following criteria:
+
+Tech Risk (not Tech Correctness, which is deferred to the reviewers)
+* **0** could be just zero impact changes, removals but no logic changes
+* **1** low impact, simple logic changes
+* **2** is anything between 1 and 3
+* **3** are extremely likely to introduce bugs
+
+Halo Risk (Externality risk)
+* **0** local change with no risk to other areas
+* **1** neighbors could be affected
+* **2** anything between 1 and 3
+* **3** things might break everywhere]
 
 ### Comments to reviewers
 
-[Info per person for what to focus on, or historical info to understand who have previously reviewed and coverage. Help them get context.]
+[Per person info for what to focus on or historical info for a new reviewer to understand who may have previously reviewed and what their coverage was. Provide context.]