Herbie

I woke up this morning to an inbox full of gifts from @mgreter 🎁 🙌

Feature

• Expose the Sass language version via the C API (@chriseppstein, #2021)

Fixes

• Incorrectly erring on comments in at-rules (@mgreter, #1233)
• Incorrectly dropping internal state of AST nodes (@mgreter, #1661)
• Incorrectly parsing the calc function (@mgreter, #1706)
• Segfault during error handling (@mgreter, #2016)
• Incorrectly identifying the selectors with type-of (@mgreter, #2020)
• Incorrectly erring on ID selectors starting with a number (@mgreter, @2023)
• Producing incorrect output when compile with MSVC (@mgreter, #2039)
• Various segfaults and incorrect output from @extend (@mgreter, #2017 #2031)