Auto-generate markdown command docs (#4451)

* Finish updating

* a couple improvements

* Update renames

* cleanup examples

docs/commands/hash_base64.md

@@ -0,0 +1,37 @@
+---
+title: hash base64
+layout: command
+version: 0.59.0
+---
+
+base64 encode or decode a value
+
+## Signature
+
+```> hash base64 ...rest --character_set --encode --decode```
+
+## Parameters
+
+ -  `...rest`: optionally base64 encode / decode data by column paths
+ -  `--character_set {string}`: specify the character rules for encoding the input.
+	Valid values are 'standard', 'standard-no-padding', 'url-safe', 'url-safe-no-padding','binhex', 'bcrypt', 'crypt'
+ -  `--encode`: encode the input as base64. This is the default behavior if not specified.
+ -  `--decode`: decode the input from base64
+
+## Examples
+
+Base64 encode a string with default settings
+```shell
+> echo 'username:password' | hash base64
+```
+
+Base64 encode a string with the binhex character set
+```shell
+> echo 'username:password' | hash base64 --character_set binhex --encode
+```
+
+Base64 decode a value
+```shell
+> echo 'dXNlcm5hbWU6cGFzc3dvcmQ=' | hash base64 --decode
+```
+