Update the language selection in the docs language switch. (GH-3114)

Change the option for `Français` into `French` to be consistent with the other language selections that are already in English.

Doc/tools/static/switchers.js

@@ -20,7 +20,7 @@
 
   var all_languages = {
       'en': 'English',
-      'fr': 'Français',
+      'fr': 'French',
       'ja': 'Japanese',
   };