Add rand command

HELP.md

@@ -437,6 +437,10 @@ Replace the current subject with "Lorem ipsum..." placeholder text.
 Can generate individual words, lines, or paragraphs.
 Example: `lipsum 4 word` -> `lorem ipsum dolor sit`
 
+#### `rand [<min=0> <max=100>]`
+Replace the current subject with a random integer between the given range (default 0-100).
+Example: `rand 3 9` -> `8`
+
 #### `convert <from> <to>`
 Assuming the current subject is a valid single data document, convert it `from` a lang `to` another lang.
 Supports: `php`|`json`