Linter for .md files?

[mcandre]

There seems to be several competing Markdown parsers (GitHub, Git Lab, Stack Overflow, Reddit...), each with their own set of accepted/rejected syntax. It would be helpful if there was a mdlint CLI / Web tool that could warn for syntax that isn't commonly accepted. Kind of like lint back in the day before C was standardized, helping coders write their .c files more portably.