selector-attribute-brackets-space-inside
Require a single space or disallow whitespace on the inside of the brackets within attribute selectors.
    [ target=_blank ]
/** ↑               ↑
 * The space inside these two brackets */The fix
option can automatically fix all of the problems reported by this
rule.
Options
string: "always"|"never"
"always"
There must always be a single space inside the brackets.
The following patterns are considered violations:
[target] {}[ target] {}[target ] {}[target=_blank] {}[ target=_blank] {}[target=_blank ] {}The following patterns are not considered violations:
[ target ] {}[ target=_blank ] {}"never"
There must never be whitespace on the inside the brackets.
The following patterns are considered violations:
[ target] {}[target ] {}[ target ] {}[ target=_blank] {}[target=_blank ] {}[ target=_blank ] {}The following patterns are not considered violations:
[target] {}[target=_blank] {}