Auto-generate markdown command docs (#4451)

* Finish updating

* a couple improvements

* Update renames

* cleanup examples

docs/commands/into_string.md

@@ -0,0 +1,69 @@
+---
+title: into string
+layout: command
+version: 0.59.0
+---
+
+Convert value to string
+
+## Signature
+
+```> into string ...rest --decimals```
+
+## Parameters
+
+ -  `...rest`: column paths to convert to string (for table input)
+ -  `--decimals {int}`: decimal digits to which to round
+
+## Examples
+
+convert decimal to string and round to nearest integer
+```shell
+> 1.7 | into string -d 0
+```
+
+convert decimal to string
+```shell
+> 1.7 | into string -d 1
+```
+
+convert decimal to string and limit to 2 decimals
+```shell
+> 1.734 | into string -d 2
+```
+
+try to convert decimal to string and provide negative decimal points
+```shell
+> 1.734 | into string -d -2
+```
+
+convert decimal to string
+```shell
+> 4.3 | into string
+```
+
+convert string to string
+```shell
+> '1234' | into string
+```
+
+convert boolean to string
+```shell
+> $true | into string
+```
+
+convert date to string
+```shell
+> date now | into string
+```
+
+convert filepath to string
+```shell
+> ls Cargo.toml | get name | into string
+```
+
+convert filesize to string
+```shell
+> ls Cargo.toml | get size | into string
+```
+