Minor cosmetic markdown tweaks in docs/cloudwatch.md (#29238)

Changed a couple codeblock types, and reformatted one yaml block to use two-spaces instead of tabs.

docs/sources/datasources/cloudwatch.md

@@ -55,7 +55,7 @@ utilize Grafana's built-in support for assuming roles.
 
 Here is a minimal policy example:
 
-```bash
+```json
 {
   "Version": "2012-10-17",
   "Statement": [
@@ -109,7 +109,7 @@ The `Assume Role ARN` field allows you to specify which IAM role to assume, if a
 
 The Grafana process in the container runs as user 472 (called "grafana"). When Kubernetes mounts your projected credentials, they will by default only be available to the root user. In order to allow user 472 to access the credentials (and avoid it falling back to the IAM role attached to the EC2 instance), you will need to provide a [security context](https://kubernetes.io/docs/tasks/configure-pod-container/security-context/) for your pod.
 
-```
+```yaml
 securityContext:
   fsGroup: 472
   runAsUser: 472
@@ -347,7 +347,7 @@ Some queries accept filters in JSON format and Grafana supports the conversion o
 
 If `env = 'production', 'staging'`, following query will return ARNs of EC2 instances which `Environment` tag is `production` or `staging`.
 
-```
+```javascript
 resource_arns(us-east-1, ec2:instance, {"Environment":${env:json}})
 ```