[Cocoa] Remove deprecated scroller part constants

NSScrollerDecrementLine and NSScrollerIncrementLine are deprecated since
macOS 10.14 without replacement, as scrollers do not have arrow buttons
anymore since macOS 10.7. Remove the constants together with the dead
switch cases in ScrollBar and Slider that handled hits on the no longer
existing scroller arrows.

Contributes to
#3214

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Author: HeikoKlare

bundles/org.eclipse.swt/Eclipse SWT PI/cocoa/org/eclipse/swt/internal/cocoa/AppKitFull.bridgesupport.extras

@@ -4504,9 +4504,7 @@
 
 	<enum name="NSScrollElasticityNone" swt_gen="true"></enum>
 	<enum name="NSScrollWheel" swt_gen="true"></enum>
-	<enum name="NSScrollerDecrementLine" swt_gen="true"></enum>
 	<enum name="NSScrollerDecrementPage" swt_gen="true"></enum>
-	<enum name="NSScrollerIncrementLine" swt_gen="true"></enum>
 	<enum name="NSScrollerIncrementPage" swt_gen="true"></enum>
 	<enum name="NSScrollerKnob" swt_gen="true"></enum>
 	<enum name="NSScrollerKnobSlot" swt_gen="true"></enum>

bundles/org.eclipse.swt/Eclipse SWT PI/cocoa/org/eclipse/swt/internal/cocoa/OS.java

@@ -2293,9 +2293,7 @@ public static Selector getSelector (long value) {
 public static final int NSImageScaleNone = 2;
 public static final int NSScrollElasticityNone = 1;
 public static final int NSScrollWheel = 22;
-public static final int NSScrollerDecrementLine = 4;
 public static final int NSScrollerDecrementPage = 1;
-public static final int NSScrollerIncrementLine = 5;
 public static final int NSScrollerIncrementPage = 3;
 public static final int NSScrollerKnob = 2;
 public static final int NSScrollerKnobSlot = 6;

bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/ScrollBar.java

@@ -481,18 +481,10 @@ void sendSelection () {
 	int hitPart = (int)((NSScroller)view).testPart(point);
 	Event event = new Event();
 	switch (hitPart) {
-	case OS.NSScrollerDecrementLine:
-		value -= increment;
-		event.detail = SWT.ARROW_UP;
-		break;
 	case OS.NSScrollerDecrementPage:
 		value -= pageIncrement;
 		event.detail = SWT.PAGE_UP;
 		break;
-	case OS.NSScrollerIncrementLine:
-		value += increment;
-		event.detail = SWT.ARROW_DOWN;
-		break;
 	case OS.NSScrollerIncrementPage:
 		value += pageIncrement;
 		event.detail = SWT.PAGE_DOWN;

bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/Slider.java

@@ -333,18 +333,10 @@ void sendSelection () {
 	int hitPart = (int)((NSScroller)view).hitPart();
 	int value = getSelection ();
 	switch (hitPart) {
-		case OS.NSScrollerDecrementLine:
-			event.detail = SWT.ARROW_UP;
-			value -= increment;
-			break;
 		case OS.NSScrollerDecrementPage:
 			value -= pageIncrement;
 			event.detail = SWT.PAGE_UP;
 			break;
-		case OS.NSScrollerIncrementLine:
-			value += increment;
-			event.detail = SWT.ARROW_DOWN;
-			break;
 		case OS.NSScrollerIncrementPage:
 			value += pageIncrement;
 			event.detail = SWT.PAGE_DOWN;