fix: unify coder create and coder delete help message (#15752)

Closes #15668

docs/reference/cli/create.md

@@ -7,7 +7,7 @@ Create a workspace
 ## Usage
 
 ```console
-coder create [flags] [name]
+coder create [flags] [workspace]
 ```
 
 ## Description

docs/reference/cli/delete.md

@@ -14,6 +14,14 @@ Aliases:
 coder delete [flags] <workspace>
 ```
 
+## Description
+
+```console
+  - Delete a workspace for another user (if you have permission):
+
+     $ coder delete <username>/<workspace_name>
+```
+
 ## Options
 
 ### --orphan