[regexp] Named capture support for string replacements

src/messages.h

Index: src/messages.h
diff --git a/src/messages.h b/src/messages.h
index e8639cf46a9a5494d7f87ca8c0bd7ab936dbe0da..2ca50d4218cd5c42ff4b2840ddd18df608824b43 100644
--- a/src/messages.h
+++ b/src/messages.h
@@ -456,6 +456,7 @@ class ErrorUtils : public AllStatic {
   T(ReduceNoInitial, "Reduce of empty array with no initial value")            \
   T(RegExpFlags,                                                               \
     "Cannot supply flags when constructing one RegExp from another")           \
+  T(RegExpInvalidReplaceString, "Invalid replacement string: '%'")             \
   T(RegExpNonObject, "% getter called on non-object %")                        \
   T(RegExpNonRegExp, "% getter called on non-RegExp object")                   \
   T(ReinitializeIntl, "Trying to re-initialize % object.")                     \