Bug 1572207 - Update AutoStableStringChars comment, r=jonco

Differential Revision: https://phabricator.services.mozilla.com/D41421

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

js/public/StableStringChars.h

@@ -35,13 +35,12 @@ MOZ_ALWAYS_INLINE size_t GetStringLength(JSString* s) {
 }
 
 /**
- * This class provides safe access to a string's chars across a GC. Once
- * we allocate strings and chars in the nursery (bug 903519), this class
- * will have to make a copy of the string's chars if they are allocated
- * in the nursery, so it's best to avoid using this class unless you really
- * need it. It's usually more efficient to use the latin1Chars/twoByteChars
- * JSString methods and often the code can be rewritten so that only indexes
- * instead of char pointers are used in parts of the code that can GC.
+ * This class provides safe access to a string's chars across a GC. If we ever
+ * nursery allocate strings' out of line chars, this class will have to make a
+ * copy, so it's best to avoid using this class unless you really need it. It's
+ * usually more efficient to use the latin1Chars/twoByteChars JSString methods
+ * and often the code can be rewritten so that only indexes instead of char
+ * pointers are used in parts of the code that can GC.
  */
 class MOZ_STACK_CLASS JS_FRIEND_API AutoStableStringChars final {
   /*