Documentation: Remove repetitive words

MIGRATION.md

@@ -5088,7 +5088,7 @@ SB 5.1.0 added [support for project root `babel.config.js` files](https://github
 
 ### React native server
 
-Storybook 5.1 contains a major overhaul of `@storybook/react-native` as compared to 4.1 (we didn't ship a version of RN in 5.0 due to timing constraints). Storybook for RN consists of an an UI for browsing stories on-device or in a simulator, and an optional webserver which can also be used to browse stories and web addons.
+Storybook 5.1 contains a major overhaul of `@storybook/react-native` as compared to 4.1 (we didn't ship a version of RN in 5.0 due to timing constraints). Storybook for RN consists of an UI for browsing stories on-device or in a simulator, and an optional webserver which can also be used to browse stories and web addons.
 
 5.1 refactors both pieces:
 

code/lib/preview-api/src/modules/store/csf/stepRunners.ts

@@ -3,7 +3,7 @@ import type { Renderer, StepRunner } from '@storybook/types';
 /**
  * Compose step runners to create a single step runner that applies each step runner in order.
  *
- * A step runner is a a function that takes a defined step: `step('label', () => { ... })`
+ * A step runner is a function that takes a defined step: `step('label', () => { ... })`
  * and runs it. The prototypical example is from `@storybook/addon-interactions` where the
  * step runner will decorate all instrumented code inside the step with information about the
  * label.

code/ui/manager/src/components/notifications/NotificationItem.stories.tsx

@@ -218,7 +218,7 @@ export const BookIconLongSubHeadline: Story = {
       content: {
         headline: 'Storybook has a book icon!',
         subHeadline:
-          'Find out more! by clicking on on buttons and downloading some applications. Find out more! by clicking on buttons and downloading some applications',
+          'Find out more! by clicking on buttons and downloading some applications. Find out more! by clicking on buttons and downloading some applications',
       },
       icon: <BookIconIcon />,
       link: undefined,

scripts/release/__tests__/ensure-next-ahead.test.ts

@@ -76,7 +76,7 @@ describe('Ensure next ahead', () => {
     expect(bumpVersion.run).toHaveBeenCalledWith({ exact: '2.1.0-alpha.0' });
   });
 
-  it('should bump version to 2.1.0-alpha.0 when main is 2.0.0 and and next is 2.0.0-rc.10', async () => {
+  it('should bump version to 2.1.0-alpha.0 when main is 2.0.0 and next is 2.0.0-rc.10', async () => {
     fsExtra.__setMockFiles({
       [CODE_PACKAGE_JSON_PATH]: JSON.stringify({ version: '2.0.0-rc.10' }),
     });