fix(hover): at rules support & refactor

[goulvenclech]

Fixes #17 and improves the logic.

What does this change?

• crates/csslsrs/src/features/hover.rs: Added the support for at_rules.
• crates/csslsrs/src/features/hover.rs: Removed the get_css_hover_content function and integrated its logic directly into the extract_hover_information function to reduce redundancy.
• crates/csslsrs/src/features/hover.rs: Refactored the extract_hover_information function to streamline the process of finding relevant CSS nodes and generating hover content.

How is it tested?

Added two new tests for at-rules in crates/csslsrs/tests/hover.rs (technically one already existed and I just unskipped it but you get it)

How is it documented?

Matches the expected behaviour.

[codspeed-hq]

CodSpeed Performance Report

Merging #20 will degrade performances by 25.49%

_{Comparing add-at-rules-hover (ad7fa43) with main (3546cf3)}

Summary

⚡ 1 improvements
❌ 1 regressions
✅ 13 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	main	add-at-rules-hover	Change
❌	weblsp - Color Presentation	671.1 µs	900.7 µs	-25.49%
⚡	weblsp - Folding Ranges	1,967.8 µs	877 µs	×2.2

[Princesseuh]

looks great