Improvements for markdown formatting (#12193)

* Fixed markdown formatting

* Resolved usage of 'shell' instead of 'yaml'

* Removed unknown 'log' keyword

content/en/docs/tasks/inject-data-application/define-environment-variable-container.md

@@ -48,7 +48,7 @@ Pod:
 
     The output is similar to this:
 
-    ```log
+    ```
     NAME            READY     STATUS    RESTARTS   AGE
     envar-demo      1/1       Running   0          9s
     ```
@@ -67,7 +67,7 @@ Pod:
 
     The output is similar to this:
 
-    ```log
+    ```
     NODE_VERSION=4.4.2
     EXAMPLE_SERVICE_PORT_8080_TCP_ADDR=10.3.245.237
     HOSTNAME=envar-demo