Minor composability etc docs changes

Signed-off-by: Fredrik Adelöw <freben@gmail.com>

packages/backend-common/README.md

@@ -8,6 +8,8 @@ error handling and similar.
 Add the library to your backend package:
 
 ```sh
+# From your Backstage root directory
+cd packages/backend
 yarn add @backstage/backend-common
 ```
 

packages/backend/src/plugins/kubernetes.ts

@@ -15,12 +15,11 @@
  */
 
 import { createRouter } from '@backstage/plugin-kubernetes-backend';
-import { Router } from 'express';
 import { PluginEnvironment } from '../types';
 
 export default async function createPlugin({
   logger,
   config,
-}: PluginEnvironment): Promise<Router> {
+}: PluginEnvironment) {
   return await createRouter({ logger, config });
 }

packages/cli/README.md

@@ -7,13 +7,13 @@ This package provides a CLI for developing Backstage plugins and apps.
 Install the package via npm or Yarn:
 
 ```sh
-$ npm install --save @backstage/cli
+npm install --save @backstage/cli
 ```
 
 or
 
 ```sh
-$ yarn add @backstage/cli
+yarn add @backstage/cli
 ```
 
 ## Development

packages/core-api/README.md

@@ -7,13 +7,13 @@ This package provides the core API used by Backstage plugins and apps.
 Do not install this package directly, it is reexported by `@backstage/core`. Install that instead:
 
 ```sh
-$ npm install --save @backstage/core
+npm install --save @backstage/core
 ```
 
 or
 
 ```sh
-$ yarn add @backstage/core
+yarn add @backstage/core
 ```
 
 ## Documentation

packages/core/README.md

@@ -7,13 +7,13 @@ This package provides the core API used by Backstage plugins and apps.
 Install the package via npm or Yarn:
 
 ```sh
-$ npm install --save @backstage/core
+npm install --save @backstage/core
 ```
 
 or
 
 ```sh
-$ yarn add @backstage/core
+yarn add @backstage/core
 ```
 
 ## Documentation

packages/dev-utils/README.md

@@ -9,13 +9,13 @@ This package provides utilities that help in developing plugins for Backstage, l
 Install the package via npm or Yarn:
 
 ```sh
-$ npm install --save-dev @backstage/dev-utils
+npm install --save-dev @backstage/dev-utils
 ```
 
 or
 
 ```sh
-$ yarn add -D @backstage/dev-utils
+yarn add -D @backstage/dev-utils
 ```
 
 ## Documentation

packages/test-utils/README.md

@@ -7,13 +7,13 @@ This package provides utilities that can be used to test plugins and apps for Ba
 Install the package via npm or Yarn:
 
 ```sh
-$ npm install --save-dev @backstage/test-utils
+npm install --save-dev @backstage/test-utils
 ```
 
 or
 
 ```sh
-$ yarn add -D @backstage/test-utils
+yarn add -D @backstage/test-utils
 ```
 
 ## Documentation

packages/theme/README.md

@@ -7,13 +7,13 @@ This package provides the extended Material UI Theme(s) that power Backstage.
 Install the package via npm or Yarn:
 
 ```sh
-$ npm install --save @backstage/theme
+npm install --save @backstage/theme
 ```
 
 or
 
 ```sh
-$ yarn add @backstage/theme
+yarn add @backstage/theme
 ```
 
 ## Documentation