Merge pull request #229971 from microsoft/tyriar/227087_3

jsdoc for selection view part

src/vs/editor/browser/viewParts/selections/selections.ts

@@ -56,6 +56,9 @@ function toStyled(item: LineVisibleRanges): LineVisibleRangesWithStyle {
  return new LineVisibleRangesWithStyle(item.lineNumber, item.ranges.map(toStyledRange));
 }
 
+/**
+ * This view part displays selected text to the user. Every line has its own selection overlay.
+ */
 export class SelectionsOverlay extends DynamicViewOverlay {
 
  private static readonly SELECTION_CLASS_NAME = 'selected-text';