src/vs/editor/common/config/editorOptions.ts/EditorLineDecorationsWidth/compute
class EditorLineDecorationsWidth:	public override compute(env: IEnvironmentalOptions, options: IComputedEditorOptions, value: number): number {
		if (value < 0) {
			// negative numbers signal a multiple
			return EditorIntOption.clampedInt(-value * env.fontInfo.typicalHalfwidthCharacterWidth, this.defaultValue, 0, 1000);
		} else {
			return value;
		}
	}