Small changes to migration guide

docs/migration.md

@@ -6,7 +6,7 @@ This document offers guidance on migrating from Prometheus 1.8 to Prometheus 2.0
 
 ## Flags
 
-The format of the Prometheus command line flags have changed.  Instead of a
+The format of the Prometheus command line flags has changed. Instead of a
 single dash, all flags now use a double dash. Common flags (`--config.file`,
 `--web.listen-address` and `--web.external-url`) are still the same but beyond
 that, almost all the storage-related flags have been removed.
@@ -50,7 +50,7 @@ alerting:
       - alertmanager:9093
 ```
 
-You can also use all the usual Prothetheus service discovery integrations and
+You can also use all the usual Prometheus service discovery integrations and
 relabeling in your Alertmanager configuration. This snippet instructs
 Prometheus to search for Kubernetes pods, in the `default` namespace, with the
 label `name: alertmanager` and with a non-empty port.
@@ -147,7 +147,7 @@ remote_read:
 
 ## PromQL
 
-The follow features have been removed from PromQL:
+The following features have been removed from PromQL:
 
 - `drop_common_labels` function - the `without` aggregation modifier should be used
   instead.
@@ -181,7 +181,7 @@ spec:
 See [https://kubernetes.io/docs/tasks/configure-pod-container/security-context/](Configure a Security Context for a Pod or Container)
 for more details.
 
-If you're using Docker, then the follow snippet would be used:
+If you're using Docker, then the following snippet would be used:
 
 ```
 docker run -u root -p 80:80 prom/prometheus:v2.0.0-rc.2  --web.listen-address :80