Let git-hyper-blame ignore new format cleanup.

Problem:  Any 'Reformat WebRTC code base' commit pollutes blame history.
Solution: Add it in ignore list.

Caveats: (from man git-hyper-blame)
  When a line skips over an ignored commit, a guess is made as to which
  commit previously modified that line, but it is not always clear where
  the line came from.
  If the ignored commit makes lots of changes in close proximity,
  in particular adding/removing/reordering lines, then the wrong
  authors may be blamed for nearby edits.

Bug: webrtc:9340
Change-Id: I0fd86e65edd6f63685c20da929a6b750fb0fb600
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/145218
Commit-Queue: Yves Gerey <yvesg@google.com>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Henrik Andreassson <henrika@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28541}
diff --git a/.git-blame-ignore-revs b/.git-blame-ignore-revs
index 8f31242..79d7a79 100644
--- a/.git-blame-ignore-revs
+++ b/.git-blame-ignore-revs
@@ -20,3 +20,5 @@
 b6760f9e4442410f2bcb6090b3b89bf709e2fce2
 # Format all C++ in WebRTC.
 665174fdbb4e0540eccb27cf7412348f1b65534c
+# Format almost all C++ in WebRTC. Again. Mostly #include reordering.
+a4d873786f10eedd72de25ad0d94ad7c53c1f68a