update cli docs

Author: zilto

docs/website/docs/reference/command-line-interface.md

@@ -89,7 +89,7 @@ Shows, converts and upgrades schemas.
 
 **Usage**
 ```sh
-dlt schema [-h] [--format {json,yaml,dbml,dot}] [--remove-defaults] file
+dlt schema [-h] [--format {json,yaml,dbml,dot,mermaid}] [--remove-defaults] file
 ```
 
 **Description**
@@ -107,7 +107,7 @@ Inherits arguments from [`dlt`](#dlt).
 
 **Options**
 * `-h, --help` - Show this help message and exit
-* `--format {json,yaml,dbml,dot}` - Display schema in this format
+* `--format {json,yaml,dbml,dot,mermaid}` - Display schema in this format
 * `--remove-defaults` - Does not show default hint values
 
 </details>
@@ -334,7 +334,7 @@ Displays default schema.
 
 **Usage**
 ```sh
-dlt pipeline [pipeline_name] schema [-h] [--format {json,yaml,dbml,dot}]
+dlt pipeline [pipeline_name] schema [-h] [--format {json,yaml,dbml,dot,mermaid}]
     [--remove-defaults]
 ```
 
@@ -350,7 +350,7 @@ Inherits arguments from [`dlt pipeline`](#dlt-pipeline).
 
 **Options**
 * `-h, --help` - Show this help message and exit
-* `--format {json,yaml,dbml,dot}` - Display schema in this format
+* `--format {json,yaml,dbml,dot,mermaid}` - Display schema in this format
 * `--remove-defaults` - Does not show default hint values
 
 </details>