Auto-generate markdown command docs (#4451)

* Finish updating

* a couple improvements

* Update renames

* cleanup examples

docs/commands/str_pascal-case.md

@@ -0,0 +1,38 @@
+---
+title: str pascal-case
+layout: command
+version: 0.59.0
+---
+
+converts a string to PascalCase
+
+## Signature
+
+```> str pascal-case ...rest```
+
+## Parameters
+
+ -  `...rest`: optionally convert text to PascalCase by column paths
+
+## Examples
+
+convert a string to PascalCase
+```shell
+> 'nu-shell' | str pascal-case
+```
+
+convert a string to PascalCase
+```shell
+> 'this-is-the-first-case' | str pascal-case
+```
+
+convert a string to PascalCase
+```shell
+> 'this_is_the_second_case' | str pascal-case
+```
+
+convert a column from a table to PascalCase
+```shell
+> [[lang, gems]; [nu_test, 100]] | str pascal-case lang
+```
+