Clarify note

Reword to improve clarity. Emphasize that changes to preference variables are not global by default.

reference/7.4/Microsoft.PowerShell.Core/About/about_Preference_Variables.md

@@ -64,9 +64,10 @@ preferences. For more information about these environment variables, see
 - `$env:PSModulePath`
 
 > [!NOTE]
-> Changes to preference variable only take effect in scripts and functions if
-> those scripts or functions are defined in the same scope as the scope in
-> which preference was used. For more information, see [about_Scopes][40].
+> Changes to preference variables apply only in the scope they are made
+> and any child scopes thereof. For example, you can limit the effects of
+> changing a preference variable to a single function or script. For more
+> information, see [about_Scopes][40].
 
 ## Working with preference variables