Bug 1510535 - Restore a few lines in .clang-format-ignore. r=tcampbell,sylvestre

Differential Revision: https://phabricator.services.mozilla.com/D13205

--HG--
extra : amend_source : 4cd337db8a968d759273e3a43aab10b1b7ee9e3f

.clang-format-ignore

@@ -16,6 +16,12 @@ js/src/builtin/intl/TimeZoneDataGenerated.h
 
 # Don't want to reformat irregexp. bug 1510128
 js/src/irregexp/.*
+
+# Generated by js/src/util/make_unicode.py
+# Note: the irregexp files are already excluded with the rest of js/src/irregexp
+# but we add them here in case that ever changes.
+js/src/irregexp/RegExpCharacters-inl.h
+js/src/irregexp/RegExpCharacters.cpp
 js/src/util/Unicode.cpp
 js/src/util/UnicodeNonBMP.h