Rename CHANGELOG to CHANGELOG.md
I propose to rename the CHANGELOG file to CHANGELOG.md, simply to prevent IDE/tools to guess the file format and wrongly assume markdown.
Since people might rely on the path, I propose the add a symlink from CHANGELOG to CHANGELOG.md, unless you folks think it's ok to break this ?
I see that the docs import the changelog as well, so maybe we can rename it without too much worries.
I looked a bit around, and didn't find a generic way to force the format of the file. Vim comments would be the best, but unsure if all the tools understand it.