Fix code snippets in PropertySource config docs (#317)

docs/src/main/asciidoc/property-source-config.adoc

@@ -79,7 +79,7 @@ data:
 Individual properties work fine for most cases but sometimes embedded `yaml` is more convenient. In this case we will
 use a single property named `application.yaml` to embed our `yaml`:
 
- ```yaml
+```yaml
 kind: ConfigMap
 apiVersion: v1
 metadata:
@@ -94,7 +94,7 @@ data:
 
 The following also works:
 
- ```yaml
+```yaml
 kind: ConfigMap
 apiVersion: v1
 metadata:
@@ -274,26 +274,29 @@ spec:
 You can select the Secrets to consume in a number of ways:
 
 1. By listing the directories where secrets are mapped:
-    ```
-    -Dspring.cloud.kubernetes.secrets.paths=/etc/secrets/db-secret,etc/secrets/postgresql
-    ```
-
-    If you have all the secrets mapped to a common root, you can set them like:
-
-    ```
-    -Dspring.cloud.kubernetes.secrets.paths=/etc/secrets
-    ```
++
+```
+-Dspring.cloud.kubernetes.secrets.paths=/etc/secrets/db-secret,etc/secrets/postgresql
+```
++
+If you have all the secrets mapped to a common root, you can set them like:
++
+```
+-Dspring.cloud.kubernetes.secrets.paths=/etc/secrets
+```
 
 2. By setting a named secret:
-    ```
-    -Dspring.cloud.kubernetes.secrets.name=db-secret
-    ```
++
+```
+-Dspring.cloud.kubernetes.secrets.name=db-secret
+```
 
 3. By defining a list of labels:
-    ```
-    -Dspring.cloud.kubernetes.secrets.labels.broker=activemq
-    -Dspring.cloud.kubernetes.secrets.labels.db=postgresql
-    ```
++
+```
+-Dspring.cloud.kubernetes.secrets.labels.broker=activemq
+-Dspring.cloud.kubernetes.secrets.labels.db=postgresql
+```
 
 .Properties:
 [options="header,footer"]