Make template documentation visible from components docs (#10611)

website/content/docs/builders/index.mdx

@@ -13,5 +13,8 @@ for various platforms. For example, there are separate builders for EC2,
 VMware, VirtualBox, etc. Packer comes with many builders by default, and can
 also be extended to add new builders.
 
-To learn more about an individual builder, choose it from the sidebar. Each
+See the [`source`](/docs/templates/hcl_templates/blocks/source) block documentation to learn more
+about configuring builders in the Packer language.
+For information on an individual builder, choose it from the sidebar. Each
 builder has its own configuration options and parameters.
+

website/content/docs/datasources/index.mdx

@@ -11,4 +11,8 @@ sidebar_title: Data Sources
 Data sources allow data to be fetched for use in Packer configuration. Use of data sources
 allows a build to use information defined outside of Packer.
 
+See the [`data`](/docs/templates/hcl_templates/datasources) block documentation to learn more
+about working with data sources. For information on an individual data source,
+choose it from the sidebar.
+
 -> **Note:** Data sources is a feature exclusively to HCL2 templates included in Packer `v1.7.0`.

website/content/docs/post-processors/index.mdx

@@ -12,3 +12,7 @@ Post-processors run after the image is built by the builder and provisioned by
 the provisioner(s). Post-processors are optional, and they can be used to
 upload artifacts, re-package, or more. For more information about
 post-processors, please choose an option from the sidebar.
+
+See [`post-processor`](/docs/templates/hcl_templates/blocks/build/post-processor) and
+[`post-processors`](/docs/templates/hcl_templates/blocks/build/post-processors)
+blocks documentations to learn more about working with post-processors.

website/content/docs/provisioners/index.mdx

@@ -17,6 +17,6 @@ use cases for provisioners include:
 - creating users
 - downloading application code
 
-See [Template Provisioners](/docs/templates/legacy_json_templates/provisioners) to learn more
+See the [`provisioner`](/docs/templates/hcl_templates/blocks/build/provisioner) block documentation to learn more
 about working with provisioners. For information on an individual provisioner,
 choose it from the sidebar.

website/content/docs/templates/hcl_templates/blocks/build/source.mdx

@@ -1,7 +1,7 @@
 ---
 description: >
   A source block nested in a build block allows you to use an already defined
-  source and to set specific fields which aren't already set in the top-level 
+  source and to set specific fields which aren't already set in the top-level
   source block.
 page_title: source - build - Blocks
 sidebar_title: <tt>source</tt>
@@ -12,26 +12,29 @@ sidebar_title: <tt>source</tt>
 `@include 'from-1.5/beta-hcl2-note.mdx'`
 
 A `source` block nested in a `build` block allows you to use an already defined
-source and to "fill in" those fields _which aren't already set in the top-level 
-source block_. 
+source and to "fill in" those fields _which aren't already set in the top-level
+source block_.
 
-Build-level source blocks are implemented by merging their contents with the 
-corresponding top-level source block, and a packer build will fail when it 
-encounters the ambiguity that arises when a source parameter is defined twice. 
-For example, in the below example, if the top-level "lxd.arch" source block 
-also defined an `output_image` field (or if one of the build-level source blocks 
+Build-level source blocks are implemented by merging their contents with the
+corresponding top-level source block, and a packer build will fail when it
+encounters the ambiguity that arises when a source parameter is defined twice.
+For example, in the below example, if the top-level "lxd.arch" source block
+also defined an `output_image` field (or if one of the build-level source blocks
 redefined and image field), Packer would error.
 
 ```hcl
-# builds.pkr.hcl
+# file: builds.pkr.hcl
 source "lxd" "arch" {
   image = "archlinux"
 }
 
 build {
+  # Use the singular `source` block set specific fields.
+  # Note that fields cannot be overwritten, in other words, you cannot
+  # set the 'image' field from the top-level source block in here, as well as
+  # the 'name' and 'output_image' fields cannot be set in the top-level source block.
   source "lxd.arch" {
-    // setting the name field allows to rename the source only for this build
-    // section.
+    # Setting the name field allows to rename the source only for this build section.
     name = "nomad"
     output_image = "nomad"
   }

website/content/docs/templates/hcl_templates/blocks/source.mdx

@@ -33,6 +33,8 @@ set specific source fields.
 build {
   source "source.amazon-ebs.example" {
     # Here Packer will use the provided ami_name instead of defaulting it.
+    # Note that fields cannot be overwritten, in other words, you cannot
+    # set the 'ami_name' field in the top-level source block.
     ami_name = "specific"
   }
 }