chore: CONFIG HELP doc added (#438)

* chore: CONFIG HELP doc added

* chore: CONFIG HELP doc added - minor styling

---------

Co-authored-by: Joe Zhou <[email protected]>

Author: vyavdoshenko

docs/command-reference/server-management/config-help.md

@@ -0,0 +1,42 @@
+---
+description:  Learn how to use Redis CONFIG HELP command to list all CONFIG subcommands and their descriptions.
+---
+
+import PageTitle from '@site/src/components/PageTitle';
+
+# CONFIG HELP
+
+<PageTitle title="Redis CONFIG HELP Command (Documentation) | Dragonfly" />
+
+## Syntax
+
+    CONFIG HELP
+
+**Time complexity:** O(1)
+
+**ACL categories:** @slow
+
+The `CONFIG HELP` command returns a helpful text describing the different `CONFIG` subcommands supported by Dragonfly.
+
+## Return
+
+[Array reply](https://redis.io/docs/latest/develop/reference/protocol-spec/#arrays): a list of subcommands and their descriptions.
+
+## Example
+
+The output of the `CONFIG HELP` command includes the following entries as implemented in Dragonfly:
+
+```shell
+dragonfly> CONFIG HELP
+ 1) CONFIG <subcommand> [<arg> [value] [opt] ...]. Subcommands are:
+ 2) GET <pattern>
+ 3)     Return parameters matching the glob-like <pattern> and their values.
+ 4) SET <directive> <value>
+ 5)     Set the configuration <directive> to <value>.
+ 6) RESETSTAT
+ 7)     Reset statistics reported by the INFO command.
+ 8) REWRITE
+ 9)     Rewrite the configuration file with the current configuration.
+10) HELP
+11)     Prints this help.
+```

docs/command-reference/server-management/config.md

@@ -22,5 +22,6 @@ Currently, the following subcommands are supported:
 - [`CONFIG GET`](./config-get.md)
 - [`CONFIG RESETSTAT`](./config-resetstat.md)
 - [`CONFIG SET`](./config-set.md)
+- [`CONFIG HELP`](./config-help.md)
 
 <!-- To see the list of available commands you can call `CONFIG HELP`. -->