Introduce a .git-blame-ignore-revs file

It for now only contains the latest commit reference, which modified a lot of
lines without any functional change.

There might be some existing commit that would benefit from being in this file
too, but it will be taken care of later if that's the case.

.git-blame-ignore-revs

@@ -0,0 +1,7 @@
+# This requires git 2.23 or later.
+#
+# You need to configure git to use this file, with something like:
+# $ git config blame.ignoreRevsFile .git-blame-ignore-revs
+
+# Introduction of ruff
+ecb8013b5f3287b51d00a4d7bf9e186cf1336b85