Add __config formatting to .git-blame-ignore-revs
diff --git a/.git-blame-ignore-revs b/.git-blame-ignore-revs
index 531eb9c..3f9fbe2 100644
--- a/.git-blame-ignore-revs
+++ b/.git-blame-ignore-revs
@@ -43,3 +43,6 @@
 
 # Use C++11 default member initializers in LLDB. NFC.
 9494c510af56d9c8593ab69017dcaa232210b235
+
+# [libc++][NFC] clang-format <__config>
+ac251726f84d5b7e6533a2e3712920184435b61b