Fix SyntaxError when an empty string is used for a rule's custom message

[mems]

If you declare empty custom message for a rule, stylelint fail with an error

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

Any

What CSS is needed to reproduce the bug?

Any

What stylelint configuration is needed to reproduce the bug?

{
  "rules": {
    "property-no-vendor-prefix": [true, {"message": ""}],
  }
}

Which version of stylelint are you using?

9.6.0

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

Node API (via gulp-stylelint)

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

No

What did you expect to happen?

No SyntaxError exception, at least an error about misconfiguration (eg. "Custom message shouldn't be empty")

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

SyntaxError: Invalid regular expression: /(^.{1,1}(\s+|$))|(^.{1,0}(\\|/|_|\.|,|;|-))/: numbers out of order in {} quantifier
    at new RegExp (<anonymous>)
    at wrapWord (<redacted>\node_modules\table\dist\wrapWord.js:24:14)
    at calculateCellHeight (<redacted>\node_modules\table\dist\calculateCellHeight.js:36:34)
    at cells.forEach (<redacted>\node_modules\table\dist\calculateRowHeightIndex.js:35:66)
    at Array.forEach (<anonymous>)
    at rows.forEach.cells (<redacted>\node_modules\table\dist\calculateRowHeightIndex.js:26:11)
    at Array.forEach (<anonymous>)
    at calculateRowHeightIndex (<redacted>\node_modules\table\dist\calculateRowHeightIndex.js:24:8)
    at Object.table (<redacted>\node_modules\table\dist\table.js:99:63)
    at formatter (<redacted>\node_modules\stylelint\lib\formatters\stringFormatter.js:135:6)
    at results.reduce (<redacted>\node_modules\stylelint\lib\formatters\stringFormatter.js:176:15)
    at Array.reduce (<anonymous>)
    at module.exports (<redacted>\node_modules\stylelint\lib\formatters\stringFormatter.js:163:20)
    at module.exports (<redacted>\node_modules\stylelint\lib\formatters\verboseFormatter.js:8:16)
    at reporter <redacted>\node_modules\gulp-stylelint\dist\reporter-factory.js:58:25)
    at <redacted>\node_modules\gulp-stylelint\dist\index.js:151:14

[jeddy3]

@mems Thanks for the clear report and for using the template.

This definitely looks like a bug (likely in the string formatter). As the issue has been labelled "help wanted", please consider contributing a fix if you'd like to help out.