docs(playwright): update docs to show include/exclude chaining (#399)

packages/playwright/README.md

@@ -83,22 +83,44 @@ new AxeBuilder({ page })
   });
 ```
 
-### AxeBuilder#include(selector: String)
+### AxeBuilder#include(selector: String | String[])
 
 Adds a CSS selector to the list of elements to include in analysis
 
 ```js
 new AxeBuilder({ page }).include('.results-panel');
 ```
 
-### AxeBuilder#exclude(selector: String)
+Method chaining is also available, add multiple CSS selectors to the list of elements to include in analysis
+
+```js
+new AxeBuilder({ page })
+  .include('.selector-one')
+  .include('.selector-two')
+  .include('.selector-three');
+```
+
+Note: arrays with more than one index when passing multiple CSS selectors are not currently supported example: ` .include(['#foo', '#bar', '#baz'])`
+
+### AxeBuilder#exclude(selector: String | String[])
 
 Add a CSS selector to the list of elements to exclude from analysis
 
 ```js
 new AxeBuilder({ page }).exclude('.another-element');
 ```
 
+Method chaining is also available, add multiple CSS selectors to the list of elements to exclude from analysis
+
+```js
+new AxeBuilder({ page })
+  .exclude('.selector-one')
+  .exclude('.selector-two')
+  .exclude('.selector-three');
+```
+
+Note: arrays with more than one index when passing multiple CSS selectors are not currently supported example: ` .exclude(['#foo', '#bar', '#baz'])`
+
 ### AxeBuilder#options(options: [axe.RunOptions](https://github.com/dequelabs/axe-core/blob/develop/doc/API.md#options-parameter))
 
 Specifies options to be used by `axe.run`. Will override any other configured options. including calls to `AxeBuilder#withRules()` and `AxeBuilder#withTags()`. See [axe-core API documentation](https://github.com/dequelabs/axe-core/blob/master/doc/API.md) for information on its structure.