Expose number of inhibited alerts in the /alerts.json response

This is so that the UI can take use of it

views.go

@@ -7,6 +7,7 @@ import (
 	"io"
 	"net/http"
 	"sort"
+	"strconv"
 	"strings"
 	"time"
 
@@ -165,6 +166,8 @@ func alerts(c *gin.Context) {
 					countLabel(counters, "@silenced", "false")
 				}
 
+				countLabel(counters, "@inhibited", strconv.FormatBool(alert.Inhibited))
+
 				for key, value := range alert.Labels {
 					if keyMap, foundKey := store.Store.Colors[key]; foundKey {
 						if color, foundColor := keyMap[value]; foundColor {

views_test.go

@@ -142,7 +142,7 @@ func TestAlerts(t *testing.T) {
 		if ur.Status != "success" {
 			t.Errorf("[%s] Invalid status in response: %s", version, ur.Status)
 		}
-		if len(ur.Counters) != 5 {
+		if len(ur.Counters) != 6 {
 			t.Errorf("[%s] Invalid number of counters in response (%d): %v", version, len(ur.Counters), ur.Counters)
 		}
 		for _, ag := range ur.AlertGroups {