mgr/dashboard: fix broken alert generator

Currently the alert generator is broken if you try to run `tox
-ealerts-fix`. I fixed it and ran the command and it built a new json
file as well.

Signed-off-by: Nizamudeen A <nia@redhat.com>

monitoring/ceph-mixin/README.md

@@ -73,4 +73,10 @@ The jsonnet code located in this directory depends on some Jsonnet third party
 libraries. To update those libraries you can run `jb update` and then update
 the generated files using `tox -egrafonnet-fix`.
 
+### Building alerts from `prometheus_alerts.libsonnet`
+
+To rebuild the `prometheus_alerts.yml` file from the corresponding libsonnet,
+you can run `tox -ealerts-fix`.
+
+
 ##### Any upgrade or downgrade to different major versions of the recommended tools mentioned above is not supported.

monitoring/ceph-mixin/alerts.jsonnet

@@ -1 +1 @@
-std.manifestYamlDoc(((import 'config.libsonnet') + (import 'alerts.libsonnet')).prometheusAlerts, indent_array_in_object=true, quote_keys=false)
+std.manifestYamlDoc((import 'mixin.libsonnet').prometheusAlerts, indent_array_in_object=true, quote_keys=false)

monitoring/ceph-mixin/jsonnetfile.lock.json

@@ -8,7 +8,7 @@
           "subdir": "grafonnet"
         }
       },
-      "version": "30280196507e0fe6fa978a3e0eaca3a62844f817",
+      "version": "a1d61cce1da59c71409b99b5c7568511fec661ea",
       "sum": "342u++/7rViR/zj2jeJOjshzglkZ1SY+hFNuyCBFMdc="
     }
   ],

monitoring/ceph-mixin/prometheus_alerts.libsonnet

@@ -236,7 +236,7 @@
           annotations: {
             documentation: 'https://docs.ceph.com/en/latest/rados/operations/health-checks#device-health-toomany',
             summary: 'Too many devices are predicted to fail, unable to resolve%(cluster)s' % $.MultiClusterSummary(),
-            description: 'The device health module has determined that devices predicted to fail can not be remediated automatically, since too many OSDs would be removed from the cluster to ensure performance and availabililty. Prevent data integrity issues by adding new OSDs so that data may be relocated.',
+            description: 'The device health module has determined that devices predicted to fail can not be remediated automatically, since too many OSDs would be removed from the cluster to ensure performance and availability. Prevent data integrity issues by adding new OSDs so that data may be relocated.',
           },
         },
         {