Custom identifiers with spaces broken in PR #397 (v1.21.9)

[agclark27]

PR #397 introduces support for minifying custom identifiers, but if those custom identifiers contain spaces in their names, the spaces are removed, breaking the interpretation of those identifiers. This behavior is not present prior to PR #397 in v1.21.8.

.test { grid-template-rows: [header-start] auto [header-end main-start] minmax(auto,1fr) [main-end footer-start] auto [footer-end];

When run against NUglify.Uglify.Css, the identifiers "header-end main-start" becomes "header-endmain-start" (space removed).

.test{grid-template-rows:[header-start] auto [header-endmain-start]minmax(auto,1fr) [main-end footer-start]auto [footer-end]

[trullock]

OK, PR welcome :)