[StickyScrolling] Move complex line adaption to central handler

[Christopher-Hermann]

Move the adaption of the sticky lines to the growing sticky lines control into the central handler class. This change simplifies the sticky lines provider, making implementations for specific languages more straightforward and maintainable.

Preparation for #2398

[github-actions]

Test Results

 1 818 files  ±0   1 818 suites  ±0   1h 35m 12s ⏱️ -11s
 7 711 tests +2   7 482 ✅ +1  228 💤 ±0  1 ❌ +1 
24 294 runs  +6  23 546 ✅ +5  747 💤 ±0  1 ❌ +1 

For more details on these failures, see this check.

Results for commit d22b414. ± Comparison against base commit d6a50a4.

This pull request removes 2 and adds 4 tests. Note that renamed tests count towards both.

org.eclipse.ui.internal.texteditor.stickyscroll.DefaultStickyLinesProviderTest ‑ testRemoveStickyLines
org.eclipse.ui.internal.texteditor.stickyscroll.DefaultStickyLinesProviderTest ‑ testSourceViewerWithDifferentModelAndWindgetLines

org.eclipse.ui.internal.texteditor.stickyscroll.StickyScrollingControlTest ‑ testShowStickyLineTextsWithSourceViewerMapping
org.eclipse.ui.internal.texteditor.stickyscroll.StickyScrollingHandlerTest ‑ testDontCalculateStickyLinesForFirstLine
org.eclipse.ui.internal.texteditor.stickyscroll.StickyScrollingHandlerTest ‑ testLineUnderStickyLine
org.eclipse.ui.internal.texteditor.stickyscroll.StickyScrollingHandlerTest ‑ testRemoveStickyLines

♻️ This comment has been updated with latest results.

[Christopher-Hermann]

Failing test is unrelated...