Improve registerFoldingRangeProvider doc (for #48526)

src/vs/vscode.d.ts

@@ -6898,9 +6898,13 @@ declare module 'vscode' {
 		/**
 		 * Register a folding range provider.
 		 *
-		 * Multiple folding can be registered for a language. In that case providers are sorted
-		 * by their [score](#languages.match) and the best-matching provider is used. Failure
-		 * of the selected provider will cause a failure of the whole operation.
+		 * Multiple providers can be registered for a language. In that case providers are asked in
+		 * parallel and the results are merged.
+		 * If multiple folding ranges start at the same position, only the range of the first registered provider is used.
+		 * If a folding range overlaps with an other range that has a smaller position, it is also ignored.
+		 *
+		 * A failing provider (rejected promise or exception) will
+		 * not cause a failure of the whole operation.
 		 *
 		 * @param selector A selector that defines the documents this provider is applicable to.
 		 * @param provider A folding range provider.