Adding support for sass files/syntax

[Martizs]

Changes

• Added: Regex logic to extract class names from .sass files, including support for nested selectors, combinators, and ampersand (&) usage.
• Added: Unit tests and fixture files for .sass class extraction in the test suite.
• Updated: README to mention experimental SASS support in the Additional Features section.

PS

• My prettier extension reformatted some unrelated lines to sass support, however configs in .prettierrc.yaml were used, hope you don't mind.
• Navigation to sass classnames seem to be working out of the box, to an extent, will make another PR for some navigation adjustments.
• Also hope you don't mind me updating the readme, would love for people to know that this extension is more than just for css files, if this PR does get merged at all :D .