Auto-generate markdown command docs (#4451)

* Finish updating

* a couple improvements

* Update renames

* cleanup examples

docs/commands/roll_left.md

@@ -0,0 +1,29 @@
+---
+title: roll left
+layout: command
+version: 0.59.0
+---
+
+Roll table columns left
+
+## Signature
+
+```> roll left --by --cells-only```
+
+## Parameters
+
+ -  `--by {int}`: Number of columns to roll
+ -  `--cells-only`: rotates columns leaving headers fixed
+
+## Examples
+
+Rolls columns to the left
+```shell
+> [[a b c]; [1 2 3] [4 5 6]] | roll left
+```
+
+Rolls columns to the left with fixed headers
+```shell
+> [[a b c]; [1 2 3] [4 5 6]] | roll left --cells-only
+```
+