Auto-generate markdown command docs (#4451)

* Finish updating

* a couple improvements

* Update renames

* cleanup examples

docs/commands/detect_columns.md

@@ -0,0 +1,17 @@
+---
+title: detect columns
+layout: command
+version: 0.59.0
+---
+
+splits contents across multiple columns via the separator.
+
+## Signature
+
+```> detect columns --skip --no_headers```
+
+## Parameters
+
+ -  `--skip {int}`: number of rows to skip before detecting
+ -  `--no_headers`: don't detect headers
+