LineNumberRulerColumn consider LineSpacing for word wrapping

[Christopher-Hermann]

The LineNumberRulerColumn should consider the text widget's LineSpacing when word wrapping is enabled.

Before the fix:

After the fix:

Fixes #2668

[Christopher-Hermann]

I tried to add unit tests, but it's too expensive to write tests since the drawing is directly done on the GC which makes it hard to assert.

[github-actions]

Test Results

 1 821 files  ±0   1 821 suites  ±0   1h 34m 25s ⏱️ - 1m 4s
 7 738 tests ±0   7 510 ✅ ±0  228 💤 ±0  0 ❌ ±0 
24 375 runs  ±0  23 626 ✅ ±0  749 💤 ±0  0 ❌ ±0 

Results for commit 34fb426. ± Comparison against base commit b3aa5b0.

[mickaelistria]

Thank you!