chore: update react imports

Signed-off-by: Paul Schultz <pschultz@pobox.com>

docs/features/search/getting-started.md

@@ -24,7 +24,6 @@ Create a new `packages/app/src/components/search/SearchPage.tsx` file in your
 Backstage app with the following contents:
 
 ```tsx
-import React from 'react';
 import { Content, Header, Page } from '@backstage/core-components';
 import { Grid, List, Card, CardContent } from '@material-ui/core';
 import {

docs/features/search/how-to-guides.md

@@ -242,8 +242,6 @@ which renderers to use. Note that the order of the renderers matters! The first
 Here is an example of customizing your `SearchPage`:
 
 ```tsx title="packages/app/src/components/searchPage.tsx"
-import React from 'react';
-
 import { Grid, Paper } from '@material-ui/core';
 import BuildIcon from '@material-ui/icons/Build';
 
@@ -325,8 +323,6 @@ export const Root = ({ children }: PropsWithChildren<{}>) => {
 Assuming you have completely customized your SearchModal, here's an example that renders results with extensions:
 
 ```tsx title="packages/app/src/components/searchModal.tsx"
-import React from 'react';
-
 import { DialogContent, DialogTitle, Paper } from '@material-ui/core';
 import BuildIcon from '@material-ui/icons/Build';