Fix typos (facebook#22494)

Author: KonstHardy

packages/react-devtools-shared/src/backend/legacy/renderer.js

@@ -716,7 +716,7 @@ export function attach(
 
     // Any time an inspected element has an update,
     // we should update the selected $r value as wel.
-    // Do this before dehyration (cleanForBridge).
+    // Do this before dehydration (cleanForBridge).
     updateSelectedElement(id);
 
     inspectedElement.context = cleanForBridge(

packages/react-dom/src/test-utils/ReactTestUtils.js

@@ -178,7 +178,7 @@ function findAllInRenderedTree(inst, test) {
 }
 
 /**
- * Finds all instance of components in the rendered tree that are DOM
+ * Finds all instances of components in the rendered tree that are DOM
  * components with the class name matching `className`.
  * @return {array} an array of all the matches.
  */
@@ -233,7 +233,7 @@ function findRenderedDOMComponentWithClass(root, className) {
 }
 
 /**
- * Finds all instance of components in the rendered tree that are DOM
+ * Finds all instances of components in the rendered tree that are DOM
  * components with the tag name matching `tagName`.
  * @return {array} an array of all the matches.
  */