[less] linter issue with digit-starting properties

[dmgawel]

• VSCode Version: 1.30.2
• OS Version: macOS 10.13.6

Steps to Reproduce:

1. Paste the following snippet in LESS file:

.spacing-mixin() {
  2xs: 0.25rem; // gives lint error: [less] at-rule or selector expected [css-ruleorselectorexpected]
  xs: 0.5rem;
  sm: 0.75rem;
}

@spacing-map: {
  2xs: 0.25rem; // gives lint error: [less] at-rule or selector expected [css-ruleorselectorexpected]
  xs: 0.5rem;
  sm: 0.75rem;
}

This compiles fine but gives lint errors in VSCode. Digit-starting properties are allowed in both mixins and maps in LESS.

Does this issue occur when all extensions are disabled?: Yes

[octref]

Fixed by microsoft/vscode-css-languageservice#135