Fix false positives for hex colours in unit-whitelist

[Bob-chemist]

Clearly describe the bug

unit-whitelist doesn't properly parse hex colors, starting with number in border property.
If hex color contains any letter except for "E" in border property, it causes error.
e.g. border: 2px solid #2196F3
If we move color to the first place of border property (border: #2196F3 2px solid) or extract it to border-color property or change it to rgb(33, 150, 243), error dissappears.
Single "E" in hex color dont't cause error because it is still a number - 2196E3 = 2196*10^3. "E" on last place or second "E" throws error too - it is not a proper number now.

Which rule, if any, is the bug related to?

unit-whitelist

What CSS is needed to reproduce the bug?

border: 2px solid #2196F3

What stylelint configuration is needed to reproduce the bug?

{
  "rules": {   
    "unit-whitelist": [
      "px"
    ]
  }
}

Which version of stylelint are you using?

12.0.1

How are you running stylelint: CLI, PostCSS plugin, Node.js API?

VS Code and stylelint extension

Does the bug relate to non-standard syntax (e.g. SCSS, Less etc.)?

"I use SASS syntax without braces"

What did you expect to happen?

"No errors to be flagged."

What actually happened (e.g. what warnings or errors did you get)?

"The following warnings were flagged:"

filter.module.sass
  Unexpected unit "F3" (unit-whitelist) stylelint(unit-whitelist) [54, 25]

[hudochenkov]

Thanks for the report and for using the template.

As I see in demo it happens only to Sass syntax: demo. Doesn't happen in standard CSS (demo) or SugarSS.

[fanich37]

It seems that the issues is caused by postcss-sass parser. When walkDecls is invoked it returns declaration with a value 2px solid 2196F3.

[jeddy3]

Closing as the syntax option was removed for the 14.0.0 release. (See the migration guide.)

Please consider opening an issue upstream and fixing the issue there as the syntax is no longer bundled by Stylelint.