cleanup, docs

site/doc/pages/shell_exec.txt

@@ -13,7 +13,5 @@ Executes a Linux shell command and returns the generated output.
 
 When command text includes user-controlled input, escape that input first with `shell_escape()`.
 
-Related:
-
-- PHP: `shell_exec()`, `exec()`, or `proc_open()`
-- JavaScript / Node.js: Node `child_process.exec()` or `spawn()`
+:example
+print("shell_exec example\n");