mkdir: add recursive directory creation example (#17172)

pages/common/mkdir.md

@@ -14,3 +14,7 @@
 - Create directories with specific permissions:
 
 `mkdir {{[-m|--mode]}} {{rwxrw-r--}} {{path/to/directory1 path/to/directory2 ...}}`
+
+- Create multiple nested directories recursively:
+
+`mkdir {{[-p|--parents]}} {{path/to/{a,b}/{x,y,z}/{h,i,j}}}`