Currently, many built-in rules support the message option's function feature:

Rough calculation:

$ git grep -l 'messageArgs: \[' lib/rules/*/index.js | wc -l
      92

And people have never complained about the feature spec, as I remember.

So, I suggest dropping experimental from this feature and officially publishing it.

Here're tasks:

• Add the function support to all rules except for deprecated ones.
• Fix the test:

  • stylelint/lib/rules/__tests__/index.test.js

    Lines 62 to 63 in 113888c

    	// NOTE: If all rules support a custom message option, we should remove this `if` statement.
    	if (!jsCode.includes('\tmessageArgs: [')) return;

• Remove the sentence from all the rule README:

  • stylelint/lib/rules/alpha-value-notation/README.md

    Line 14 in 113888c

    The [`message` secondary option](../../../docs/user-guide/configure.md#message) can accept the arguments of this rule.

• Remove "Experimental feature" wording from the doc:

  • stylelint/docs/user-guide/configure.md

    Line 114 in 113888c

    Experimental feature: some rules support message arguments. For example, when configuring the `color-no-hex` rule, the hex color can be used in the message string: