Add .git-blame-ignore-revs (#4743)

* Add .git-blame-ignore-revs

* Add readme comment

* Add "changed to 80 max column"

.git-blame-ignore-revs

@@ -0,0 +1,14 @@
+# If a commit modifies a ton of files and doesn't really contribute to the
+# output of git-blame, please add it here
+#
+# Don't add commits from the same PR you are creating. We squash PRs into a
+# single commit, so references to those commits will be lost
+#
+# 2018 - changed to 80 max column
+f71ff08e686ae76c3dd4084d0f05f27ba9b3fdcb
+#
+# 2018 - added brace wrapping after if and for
+e259b9e39f46f3cb0e4838c988d4f320a03dfaa4
+#
+# 2019 - Normalize line endings in already existing files
+b06eb9df835c25154899fbcf43e9b37addcea1b1

README.md

@@ -44,6 +44,18 @@ git submodule update --init --recursive
 
 [Building on FreeBSD](../master/BUILDING_ON_FREEBSD.md)
 
+## Git blame
+
+This project has big commits in the history which for example update all line
+endings. To improve the output of git-blame, consider setting:
+
+```
+git config blame.ignoreRevsFile .git-blame-ignore-revs
+```
+
+This will ignore all revisions mentioned in the [`.git-blame-ignore-revs`
+file](./.git-blame-ignore-revs). GitHub does this by default.
+
 ## Code style
 
 The code is formatted using clang format in Qt Creator. [.clang-format](src/.clang-format) contains the style file for clang format.