doc: update VM section text

This commit updates the VM section with suggestion for a minor
improvement (hopefully) of the text.

PR-URL: #20595
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

doc/api/vm.md

@@ -17,8 +17,8 @@ The sandboxed code uses a different V8 Context, meaning that
 it has a different global object than the rest of the code.
 
 One can provide the context by ["contextifying"][contextified] a sandbox
-object. The sandboxed code treats any property on the sandbox like a
-global variable. Any changes on global variables caused by the sandboxed
+object. The sandboxed code treats any property in the sandbox like a
+global variable. Any changes to global variables caused by the sandboxed
 code are reflected in the sandbox object.
 
 ```js