add version types

website/source/docs/commands/index.html.md

@@ -71,7 +71,7 @@ This makes it more convenient to parse using standard Unix tools such as `awk` o
 The format is:
 
 ``` text
-timestamp,,target,type,data...
+timestamp,target,type,data...
 ```
 
 Each component is explained below:
@@ -101,7 +101,9 @@ become a literal `\r`.
 
 ### Machine-Readable Message Types
 
-There are two common message types for the Machine Readable output:
+Here's an incomplete list of types you may see in the machine-readable output:
+
+You'll see these data types when you run `packer build`:
 
 -  `ui`: this means that the information being provided is a human-readable string
   that would be sent to stdout even if we aren't in machine-readable mode. There
@@ -115,6 +117,9 @@ There are two common message types for the Machine Readable output:
 
     -  `error`: reserved for errors
 
+- `artifact-count`: This data type tells you how many artifacts a particular
+  build produced.
+
 - `artifact`: This data type tells you information about what Packer created
   during its build. An example of output follows the pattern
   `timestamp, buildname, artifact, artifact_number, key, value` where `key` and
@@ -139,6 +144,16 @@ There are two common message types for the Machine Readable output:
         1539967803,amazon-ebs,artifact,1,end
       ```
 
+You'll see these data types when you run `packer version`:
+
+- `version`: what version of Packer is running
+
+- `version-prerelease`: Data will contain `dev` if version is prerelease, and
+  otherwise will be blank.
+
+- `version-commit`: The git hash for the commit that the branch of Packer is
+  currently on; most useful for Packer developers.
+
 ## Autocompletion
 
 The `packer` command features opt-in subcommand autocompletion that you can