docs(visible): Add docs for visible() method

Author: Toilal

docs/en/SUMMARY.md

@@ -48,6 +48,7 @@
     * [text](api/wrapper/text.md)
     * [trigger](api/wrapper/trigger.md)
     * [update](api/wrapper/update.md)
+    * [visible](api/wrapper/visible.md)
   * [WrapperArray](api/wrapper-array/README.md)
     * [at](api/wrapper-array/at.md)
     * [contains](api/wrapper-array/contains.md)
@@ -63,6 +64,7 @@
     * [setProps](api/wrapper-array/setProps.md)
     * [trigger](api/wrapper-array/trigger.md)
     * [update](api/wrapper-array/update.md)
+    * [visible](api/wrapper/visible.md)
   * [components](api/components/README.md)
     * [TransitionStub](api/components/TransitionStub.md)
     * [TransitionGroupStub](api/components/TransitionGroupStub.md)

docs/en/api/wrapper/visible.md

@@ -0,0 +1,21 @@
+# exists()
+
+Assert `Wrapper` or `WrapperArray` is visible.
+
+Returns false if an ancestor element has `display: none` or `visibility: hidden` style.
+
+- **Returns:** `{boolean}`
+
+- **Example:**
+
+```js
+import { mount } from 'vue-test-utils'
+import { expect } from 'chai'
+import Foo from './Foo.vue'
+
+const wrapper = mount(Foo)
+expect(wrapper.visible()).toBe(true)
+expect(wrapper.find('is-not-visible').visible()).toBe(false)
+expect(wrapper.findAll('div').visible()).toBe(true)
+expect(wrapper.findAll('is-not-visible').visible()).toBe(false)
+```