Update vanilla install notes with escape character note

Signed-off-by: Varun Srinivasan <varuns6@vmware.com>

docs/vanilla.md

@@ -78,6 +78,10 @@ port = "443"
 % kubectl -n <velero-namespace> create secret generic velero-vsphere-config-secret --from-file=csi-vsphere.conf
 ```
 
+**NOTE:** If the configuration values contain [Golang escape characters](https://yourbasic.org/golang/multiline-string/), please ensure it is properly escaped. See example below.
+
+If your VC password is `pwd\123`, the configuration file's password key-value should be `password = "pwd\\123"`.
+
 ### Create Velero vSphere Plugin Config
 
 The config map provides information about the cluster flavor and VC Credential Secret created in the previous step during
@@ -157,6 +161,7 @@ port = "443"
 % kubectl -n <velero-namespace> create secret generic velero-vsphere-config-secret --from-file=csi-vsphere.conf
 ```
 
+
 ### Create Velero vSphere Plugin Configuration
 
 The config map provides information about the cluster flavor and VC Credential Secret created in the previous step during