documentation updates for volume context and params

website/pages/docs/commands/volume/register.mdx

@@ -49,6 +49,12 @@ mount_options {
 secrets {
    example_secret = "xyzzy"
 }
+parameters {
+    skuname = "Premium_LRS"
+}
+context {
+    endpoint = "http://192.168.1.101:9425"
+}
 ```
 
 ## Volume Specification Parameters
@@ -87,9 +93,21 @@ secrets {
   - `fs_type`: file system type (ex. `"ext4"`)
   - `mount_flags`: the flags passed to `mount` (ex. `"ro,noatime"`)
 
-- `secrets` <code>(map:nil)</code> - An optional key-value map of
-  strings used as credentials for publishing and unpublishing volumes.
-
+- `secrets` <code>(map<string|string>:nil)</code> - An optional
+  key-value map of strings used as credentials for publishing and
+  unpublishing volumes.
+
+- `parameters` <code>(map<string|string>:nil)</code> - An optional
+  key-value map of strings passed directly to the CSI plugin to
+  configure the volume. The details of these parameters are specific
+  to each storage provider, so please see the specific plugin
+  documentation for more information.
+
+- `context` <code>(map<string|string>:nil)</code> - An optional
+  key-value map of strings passed directly to the CSI plugin to
+  validate the volume. The details of these parameters are specific to
+  each storage provider, so please see the specific plugin
+  documentation for more information.
 
 [volume_specification]: #volume-specification
 [csi]: https://github.com/container-storage-interface/spec