Give every condition a headline, an explanation and a resolved line in plain words

The operator could not read the desktop notifications: they carried plan ids,
commits, keys and verb syntax. The words the operator reads now travel with the
condition, so every channel says them (hq ADR 0253).

cmd/mesh-controller/machine_units.go

@@ -90,8 +90,9 @@ func machineUnitsObservation(node string, u *link.UnitsHealth) (conditions.Obser
 	if len(u.Failed) == 0 {
 		return o, false
 	}
-	var names, said []string
+	var names, said, plain []string
 	for _, f := range u.Failed {
+		plain = append(plain, unitPlainWords(f.Unit))
 		where := ""
 		if f.Scope == "user" {
 			where = " (the account's own manager)"
@@ -111,6 +112,14 @@ func machineUnitsObservation(node string, u *link.UnitsHealth) (conditions.Obser
 		"Each is the machine's own: mend or remove it there, or have a module place it",
 		node, len(u.Failed), strings.Join(names, ", "))
 	o.Said = strings.Join(said, "; ")
+	failed := "1 failed service"
+	if len(u.Failed) > 1 {
+		failed = fmt.Sprintf("%d failed services", len(u.Failed))
+	}
+	o.Headline = fmt.Sprintf("%s on %s", conditions.Capital(failed), node)
+	o.Explanation = fmt.Sprintf("On %s, %s failed. No module manages them, so the mesh does not repair them: mend or "+
+		"remove them on %s.", node, namesWords(plain, 3), node)
+	o.Resolved = "No failed services on " + node + " any more"
 	return o, true
 }