Auto-generate markdown command docs (#4451)

* Finish updating

* a couple improvements

* Update renames

* cleanup examples

docs/commands/each_window.md

@@ -0,0 +1,30 @@
+---
+title: each window
+layout: command
+version: 0.59.0
+---
+
+Runs a block on window groups of `window_size` that slide by n rows.
+
+## Signature
+
+```> each window (window_size) (block) --stride```
+
+## Parameters
+
+ -  `window_size`: the size of each window
+ -  `block`: the block to run on each window
+ -  `--stride {int}`: the number of rows to slide over between windows
+
+## Examples
+
+A sliding window of two elements
+```shell
+> echo [1 2 3 4] | each window 2 { $it.0 + $it.1 }
+```
+
+A sliding window of two elements, with a stride of 3
+```shell
+> [1, 2, 3, 4, 5, 6, 7, 8] | each window 2 --stride 3 { |x| $x.0 + $x.1 }
+```
+