Format docs markdown

Signed-off-by: Stefan Prodan <stefan.prodan@gmail.com>

docs/gitbook/tutorials/prometheus-operator.md

@@ -1,10 +1,11 @@
 # Canary analysis with Prometheus Operator
 
-This guide show you how to use Prometheus Operator for canary analysis.
+This guide show you how to use
+[Prometheus Operator](https://github.com/prometheus-operator/prometheus-operator) for canary analysis.
 
 ## Prerequisites
 
-Flagger requires a Kubernetes cluster **v1.16** or newer.
+Flagger requires a Kubernetes cluster **v1.16** or newer and Prometheus Operator **v0.40** or newer.
 
 Install Prometheus Operator with Helm v3:
 
@@ -19,7 +20,7 @@ helm upgrade -i prometheus prometheus-community/kube-prometheus-stack \
 ```
 
 The `prometheus.prometheusSpec.serviceMonitorSelectorNilUsesHelmValues=false`
-option allows Prometheus operator to watch serviceMonitors outside of his namespace.
+option allows Prometheus Operator to watch serviceMonitors outside of its namespace.
 
 Install Flagger by setting the metrics server to Prometheus:
 
@@ -40,7 +41,7 @@ helm upgrade -i loadtester flagger/loadtester \
 --namespace flagger-system
 ```
 
-Install podinfo demo app:
+Install [podinfo](https://github.com/stefanprodan/podinfo) demo app:
 
 ```bash
 helm repo add podinfo https://stefanprodan.github.io/podinfo
@@ -53,23 +54,8 @@ helm upgrade -i podinfo podinfo/podinfo \
 
 ## Service monitors
 
-The demo app is instrumented with Prometheus so you can create service monitors to scrape podinfo's metrics endpoint:
-
-```yaml
-apiVersion: monitoring.coreos.com/v1
-kind: ServiceMonitor
-metadata:
-  name: podinfo-primary
-  namespace: test
-spec:
-  endpoints:
-  - path: /metrics
-    port: http
-    interval: 5s
-  selector:
-    matchLabels:
-      app: podinfo
-```
+The demo app is instrumented with Prometheus,
+so you can create a `ServiceMonitor` objects to scrape podinfo's metrics endpoint:
 
 ```yaml
 apiVersion: monitoring.coreos.com/v1
@@ -85,10 +71,24 @@ spec:
   selector:
     matchLabels:
       app: podinfo-canary
+---
+apiVersion: monitoring.coreos.com/v1
+kind: ServiceMonitor
+metadata:
+  name: podinfo-primary
+  namespace: test
+spec:
+  endpoints:
+    - path: /metrics
+      port: http
+      interval: 5s
+  selector:
+    matchLabels:
+      app: podinfo
 ```
 
 We are setting `interval: 5s` to have a more aggressive scraping.
-If you do not define it, you must to use a longer interval in the Canary object.
+If you do not define it, you should use a longer interval in the Canary object.
 
 ## Metric templates
 
@@ -197,4 +197,3 @@ Based on the above specification, Flagger creates the primary and canary Kuberne
 
 During the canary analysis, Prometheus will scrape the canary service and Flagger will use the HTTP error rate
 and latency queries to determine if the release should be promoted or rolled back.
-