bug 1504440: geckodriver: fix warning about peer review; r=whimboo

The warning talks about the Marionette Python client, but this
is geckodriver.

Differential Revision: https://phabricator.services.mozilla.com/D10811

--HG--
extra : moz-landing-system : lando

testing/geckodriver/src/prefs.rs

@@ -2,10 +2,10 @@ use mozprofile::preferences::Pref;
 
 // ALL CHANGES TO THIS FILE MUST HAVE REVIEW FROM A GECKODRIVER PEER!
 //
-// The Marionette Python client is used out-of-tree with release
-// channel builds of Firefox.  Removing a preference from this file
-// will cause regressions, so please be careful and get review from
-// a Testing :: Marionette peer before you make any changes to this file.
+// geckodriver is used out-of-tree with release channel builds of Firefox.
+// Removing a preference from this file will cause regressions,
+// so please be careful and get review from a Testing :: geckodriver peer
+// before you make any changes to this file.
 
 lazy_static! {
     pub static ref DEFAULT: Vec<(&'static str, Pref)> = vec![