website: Use hcl code language fences instead of terraform/tf (#824)

The developer website rendering currently only supports `hcl`.

Author: bflad

website/docs/plugin/framework/data-sources/timeouts.mdx

@@ -26,7 +26,7 @@ Terraform configuration.
 
 If your configuration is using a nested block to define timeouts, such as the following:
 
-```terraform
+```hcl
 resource "timeouts_example" "example" {
   /* ... */
 
@@ -61,7 +61,7 @@ func (d *ThingDataSource) Schema(ctx context.Context, req datasource.SchemaReque
 
 If your configuration is using nested attributes to define timeouts, such as the following:
 
-```terraform
+```hcl
 resource "timeouts_example" "example" {
   /* ... */
 

website/docs/plugin/framework/handling-data/terraform-concepts.mdx

@@ -96,7 +96,7 @@ right order, and when a provider, resource, or data source relies on a value
 from another provider, resource, or data source that has not been resolved yet,
 it represents that state by using the unknown value. For example:
 
-```tf
+```hcl
 resource "example_foo" "bar" {
   hello = "world"
   demo = true

website/docs/plugin/framework/migrating/benefits.mdx

@@ -293,7 +293,7 @@ Version 6 lets you declare schemas with nested attributes in addition to blocks.
 
 In the following configuration example, a schema uses a list block that is difficult to dynamically configure.
 
-```terraform
+```hcl
 locals {
   calls = toset([
     {call_me: “example1”, maybe: true},
@@ -315,7 +315,7 @@ resource “examplecloud_thing” “example” {
 
 In the following configuration example, a schema uses list nested attributes to simplify the configuration.
 
-```terraform
+```hcl
 locals {
   calls = [
     {call_me: “example1”, maybe: true},

website/docs/plugin/framework/migrating/data-sources/timeouts.mdx

@@ -24,7 +24,7 @@ Terraform configuration.
 
 If your configuration is using a nested block to define timeouts, such as the following:
 
-```terraform
+```hcl
 resource "timeouts_example" "example" {
   /* ... */
 
@@ -59,7 +59,7 @@ func (d *ThingDataSource) Schema(ctx context.Context, req datasource.SchemaReque
 
 If your configuration is using nested attributes to define timeouts, such as the following:
 
-```terraform
+```hcl
 resource "timeouts_example" "example" {
   /* ... */
 

website/docs/plugin/framework/migrating/resources/timeouts.mdx

@@ -24,7 +24,7 @@ Terraform configuration.
 
 If your configuration is using a nested block to define timeouts, such as the following:
 
-```terraform
+```hcl
 resource "timeouts_example" "example" {
   /* ... */
 
@@ -61,7 +61,7 @@ func (t *exampleResource) Schema(ctx context.Context, req resource.SchemaRequest
 
 If your configuration is using nested attributes to define timeouts, such as the following:
 
-```terraform
+```hcl
 resource "timeouts_example" "example" {
   /* ... */
 

website/docs/plugin/framework/providers/index.mdx

@@ -208,7 +208,7 @@ Not all values are guaranteed to be
 For example, if a practitioner interpolates a resource's unknown value into the block,
 that value may show up as unknown depending on how the graph executes:
 
-```tf
+```hcl
 resource "random_string" "example" {}
 
 provider "examplecloud" {

website/docs/plugin/framework/resources/timeouts.mdx

@@ -26,7 +26,7 @@ Terraform configuration.
 
 If your configuration is using a nested block to define timeouts, such as the following:
 
-```terraform
+```hcl
 resource "timeouts_example" "example" {
   /* ... */
 
@@ -63,7 +63,7 @@ func (t *exampleResource) Schema(ctx context.Context, req resource.SchemaRequest
 
 If your configuration is using nested attributes to define timeouts, such as the following:
 
-```terraform
+```hcl
 resource "timeouts_example" "example" {
   /* ... */