Bug fix: Make filenames with dots work with at-import-partial-extension rule

[kersh]

Bug

• Related issue: Rule "scss/at-import-partial-extension" is too broad #587 (comment)
• Fixing an issue when using @import with scss files that contain . symbol.

Before (didn't work)

@import "colors.variables"; // <--- Stylelint: Unexpected extension ".utility" in @import (scss/at-import-partial-extension)
@import "defaultOutlineStyle.mixin"; // <--- Stylelint: Unexpected extension ".utility" in @import (scss/at-import-partial-extension)

// ...

After (works now)

@import "colors.variables"; // OK
@import "defaultOutlineStyle.mixin"; // OK

// ...

[kersh]

So extension contains after dot value (in my case it is .variables or .mixin).
I assume we only care about checking if there is a .scss file partial since we work with Sass. Other extension values can be left in the code and linter shouldn't highlight them.

[kristerkari]

👍

[kristerkari]

Looks good 👍