[clang] [clang-tools-extra] [flang] [lldb] [llvm] [openmp] [pstl] Finally formalise our defacto line-ending policy (PR #86318)

[Martin Storsjö via cfe-commits]

mstorsjo wrote:

> I think this is due to a subtly of config. Setting `core.autocrlf` to `false` doesn't actually do anything since it's the default. 

In Git for Windows, the default actually is `core.autocrlf` set to `true`. When manually installing, the installer wizard used to ask the user which way they want their defaults to be set, not sure if this still is the case. But in e.g. Github Actions runners, you get it set to `true` by default - see https://github.com/mstorsjo/llvm-project/actions/runs/11459095411/job/31882864878.

https://github.com/llvm/llvm-project/pull/86318