prom: try to fix links in cheat sheet

service/prometheus.md

@@ -1003,6 +1003,8 @@ day:
 
 Those are visible in the [main Grafana dashboard][].
 
+[main Grafana dashboard]: https://grafana.torproject.org/d/wUmZB05Zk/tpo-overview
+
 [Number of machines][]:
 
     count(up{job="node"})
@@ -1011,16 +1013,16 @@ Those are visible in the [main Grafana dashboard][].
 
     count(node_os_info) by (version_id, version_codename)
 
-[Number of machines per exporters, or technically, number of machines per job][]:
+[Number of machines per exporters][], or technically, number of machines per job:
 
-    sort_desc(sum(up{job=~\"$job\"}) by (job)
+    sort_desc(sum(up{job=~"$job"}) by (job)
 
 [Number of CPU cores, memory size, file system and LVM sizes][]:
 
-    count(node_cpu_seconds_total{classes=~\"$class\",mode=\"system\"})
-    sum(node_memory_MemTotal_bytes{classes=~\"$class\"}) by (alias)
-    sum(node_filesystem_size_bytes{classes=~\"$class\"}) by (alias)
-    sum(node_volume_group_size{classes=~\"$class\"}) by (alias)
+    count(node_cpu_seconds_total{classes=~"$class",mode="system"})
+    sum(node_memory_MemTotal_bytes{classes=~"$class"}) by (alias)
+    sum(node_filesystem_size_bytes{classes=~"$class"}) by (alias)
+    sum(node_volume_group_size{classes=~"$class"}) by (alias)
 
 See also the [CPU][], [memory][], and [disk][] dashboards.
 
@@ -1030,10 +1032,9 @@ See also the [CPU][], [memory][], and [disk][] dashboards.
 
 [Number of machines]: https://prometheus.torproject.org/graph?g0.expr=count(up{job%3D"node"})
 [Number of machine per OS version]: https://prometheus.torproject.org/graph?g0.expr=count(node_os_info)+by+(version_id,+version_codename)
-[Number of machines per exporters, or technically, number of machines per job]: https://prometheus.torproject.org/graph?g0.expr=sort_desc(sum(up{job%3D~\"$job\"})+by+(job)
+[Number of machines per exporters]: https://prometheus.torproject.org/graph?g0.expr=sort_desc(sum(up{job%3D~\"$job\"})+by+(job)
 [Number of CPU cores, memory size, file system and LVM sizes]: https://prometheus.torproject.org/graph?g0.expr=count(node_cpu_seconds_total{classes%3D~\"$class\",mode%3D\"system\"})
 [Uptime, in days]: https://prometheus.torproject.org/graph?g0.expr=round((time()+-+node_boot_time_seconds)+/+(24*60*60))
-[main Grafana dashboard]: https://grafana.torproject.org/d/wUmZB05Zk/tpo-overview
 [CPU]: https://grafana.torproject.org/d/gex9eLcWz/cpu-usage
 [memory]: https://grafana.torproject.org/d/amgrk2Qnk/memory-usage
 [disk]: https://grafana.torproject.org/d/zbCoGRjnz/disk-usage?from=now-24h&to=now&var-class=All&var-node=All