validateAttributeSeparator multiLineSeparator doesn't support variable indenting

[GPetrites]

This rule is probably the most important for us. When you use Angular you eventually learn that Pug doesn't recognize the Angular binding attributes correctly unless you separate them with a comma. Missing a comma has bitten us numerous times.

currently when you configure the rule using:

"validateAttributeSeparator": {
    "separator": ", ",
    "multiLineSeparator": ",\n  "
}

The pug is only considered valid if the white space on the second line matches EXACTLY the white space included in the rule. As I have it above, there are two spaces after the newline so the rule only passed if the pug looks like:

div(
    aaa="111",
  bbb="222"
)

Note that there are exactly two spaces before the 'bbb' attribute. If I add or remove a space, the rule reports it as an error.

If I replace the spaces with tabs in both the rule and the pug, I get the same results. The number of tabs in the rule must match exactly the number of tabs in the pug.

As a result, it's not possible to create a rule that allows the following pug to be recognized as valid:

div(
    aaa="aaa",
    bbb="bbb"
)
    div(
        aaa="aaa",
        bbb="bbb"
    )
        div(
            aaa="aaa",
            bbb="bbb"
        )

In order to be usable, the multiLineSeparator needs to support various levels of indenting on the following line.

[adrienverge]

I just did a test and confirm what you experience. A new option would be great, for instance:

"validateAttributeSeparator": {
    "separator": ", ",
    "allowMultiLine": true  # `allowMultiLine` and `multiLineSeparator` should be mutually exclusive
}

Contributions are welcome!