Auto-generate markdown command docs (#4451)

* Finish updating

* a couple improvements

* Update renames

* cleanup examples

docs/commands/from_eml.md

@@ -0,0 +1,36 @@
+---
+title: from eml
+layout: command
+version: 0.59.0
+---
+
+Parse text as .eml and create table.
+
+## Signature
+
+```> from eml --preview-body```
+
+## Parameters
+
+ -  `--preview-body {int}`: How many bytes of the body to preview
+
+## Examples
+
+Convert eml structured data into table
+```shell
+> 'From: test@email.com
+Subject: Welcome
+To: someone@somewhere.com
+
+Test' | from eml
+```
+
+Convert eml structured data into table
+```shell
+> 'From: test@email.com
+Subject: Welcome
+To: someone@somewhere.com
+
+Test' | from eml -b 1
+```
+