plugin/how-terraform-works: Further clarify nested attributes benefits (#76)

Reference: hashicorp/terraform-plugin-framework#214
Reference: hashicorp/terraform-plugin-sdk#819
Reference: hashicorp/terraform-plugin-sdk#201

As part of investigating some differences between sdk/v2 and framework, the individual sensitivity configuration offered by nested attributes in protocol version 6 is important to call out explicitly.

Author: bflad

website/docs/plugin/how-terraform-works.mdx

@@ -123,7 +123,9 @@ Major versions of the protocol delineate Terraform CLI and Terraform Plugin comp
 
 Protocol version 6 is compatible with Terraform CLI version 1.0 and later. Protocol version 6 includes all version 5 functionality for providers, plus:
 
-* **Nested Attributes**: You can define `SchemaAttribute` with the `NestedType` field. This enables complex schemas using [argument syntax](/language/syntax/configuration#arguments) instead of [block syntax](/language/syntax/configuration#blocks) and is preferred going forward.
+* **Nested Attributes**: Define `SchemaAttribute` with the `NestedType` field.
+    * Enable practitioners to use easier [argument syntax](/language/syntax/configuration#arguments) instead of [block syntax](/language/syntax/configuration#blocks).
+    * Configure value sensitivity on individual nested attributes, rather than an entire read-only (`Computed` only) attribute.
 
 Implementations include: