Update the alert digest wording

internal/forecast/derive.go

@@ -65,6 +65,7 @@ type AlertOverlap struct {
 	Period      timeutil.Period `json:"period"`
 	Overlap     timeutil.Period `json:"overlap"`
 	Description string          `json:"description,omitempty"`
+	Instruction string          `json:"instruction,omitempty"`
 }
 
 type PrecipTiming struct {
@@ -463,6 +464,7 @@ func AlertOverlaps(alertRun *weatherdata.AlertRun, period timeutil.Period) []Ale
 			Period:      alert.Period,
 			Overlap:     intersect(alert.Period, period),
 			Description: alert.Description,
+			Instruction: alert.Instruction,
 		})
 	}
 	sort.SliceStable(overlaps, func(i int, j int) bool {
@@ -476,6 +478,7 @@ type parsedAlert struct {
 	Headline    string
 	Severity    string
 	Description string
+	Instruction string
 	Period      timeutil.Period
 }
 
@@ -488,7 +491,8 @@ func parseAlert(raw json.RawMessage) (parsedAlert, bool) {
 		Event:       stringField(fields, "event"),
 		Headline:    firstStringField(fields, "headline", "title"),
 		Severity:    stringField(fields, "severity"),
-		Description: firstStringField(fields, "description", "instruction"),
+		Description: stringField(fields, "description"),
+		Instruction: stringField(fields, "instruction"),
 	}
 	start, startOK := firstTimeField(fields, "onset", "startsAt", "startTime", "effective", "sent")
 	end, endOK := firstTimeField(fields, "ends", "endsAt", "endTime", "expires")