Consider using regular folding icons for manual or preserved folding ranges. Fixes microsoft#156279 (microsoft#156573)

Author: aeschli

src/vs/editor/contrib/folding/browser/folding.css

@@ -32,6 +32,3 @@
 	cursor: pointer;
 }
 
-.monaco-editor .margin-view-overlays .codicon.codicon-folding-manual-expanded::before {
-	transform: rotate(90deg);
-}

src/vs/editor/contrib/folding/browser/foldingDecorations.ts

@@ -14,8 +14,8 @@ import { ThemeIcon } from 'vs/platform/theme/common/themeService';
 
 export const foldingExpandedIcon = registerIcon('folding-expanded', Codicon.chevronDown, localize('foldingExpandedIcon', 'Icon for expanded ranges in the editor glyph margin.'));
 export const foldingCollapsedIcon = registerIcon('folding-collapsed', Codicon.chevronRight, localize('foldingCollapsedIcon', 'Icon for collapsed ranges in the editor glyph margin.'));
-export const foldingManualCollapsedIcon = registerIcon('folding-manual-collapsed', Codicon.ellipsis, localize('foldingManualCollapedIcon', 'Icon for manually collapsed ranges in the editor glyph margin.'));
-export const foldingManualExpandedIcon = registerIcon('folding-manual-expanded', Codicon.ellipsis, localize('foldingManualExpandedIcon', 'Icon for manually expanded ranges in the editor glyph margin.'));
+export const foldingManualCollapsedIcon = registerIcon('folding-manual-collapsed', foldingCollapsedIcon, localize('foldingManualCollapedIcon', 'Icon for manually collapsed ranges in the editor glyph margin.'));
+export const foldingManualExpandedIcon = registerIcon('folding-manual-expanded', foldingExpandedIcon, localize('foldingManualExpandedIcon', 'Icon for manually expanded ranges in the editor glyph margin.'));
 
 export class FoldingDecorationProvider implements IDecorationProvider {