Support EditorConfig for configuration

[ejball]

It would be great if we could configure markdownlint in an .editorconfig file. The syntax could be very similar to the JSON configuration, e.g. the options.config example could look something like this:

[*.md]
markdownlint.default = true
markdownlint.MD003.style = atx_closed
markdownlint.MD007.indent = 4
markdownlint.no_hard_tabs = false
markdownlint.whitespace = false

[DavidAnson]

Do you mean for the markdownlint CLI and/or VS Code extension? This library already supports alternate parsers for configuration: https://github.com/DavidAnson/markdownlint#parsers

[ejball]

Do you mean for the markdownlint CLI and/or VS Code extension?

Yes, sorry about that; should I reopen this case at vscode-markdownlint and/or markdownlint-cli? Does one use the other, or are they independent? (My primary interest is in the VS Code extension.)

[DavidAnson]

No worries! They are independent projects, though I own one and am a significant contributor for the other. I think this is most applicable for VS Code, but if there is history of CLI lint tools supporting this file, it would make sense there, too. Thanks!

[ejball]

Moved to DavidAnson/vscode-markdownlint#120