htop: add readonly example (#18318)

Author: Managor

pages/common/htop.md

@@ -23,14 +23,14 @@
 
 `htop {{[-d|--delay]}} {{50}}`
 
+- Disable all system and process changing features:
+
+`htop --readonly`
+
 - See interactive commands while running htop:
 
-`<?>`
+`{{<F1>|<?>}}`
 
 - Switch to a different tab:
 
 `<Tab>`
-
-- Display help:
-
-`htop {{[-h|--help]}}`