Tidy up README.

Tech writing style fixes:

- avoid unnecessary use of the passive voice
- prefer imperative over present continuous in headings
- use a separate paragraph for the point about accessibility standards

Remove confusing information about GOV.UK Docker. Docker isn't necessary
for development work on this gem.

README.md

@@ -4,65 +4,67 @@
 [![JavaScript Style Guide](https://img.shields.io/badge/code_style-standard-brightgreen.svg)](https://standardjs.com)
 [![Stylelint Style Guide](https://img.shields.io/badge/code_style-stylelint-brightgreen.svg)](https://github.com/alphagov/stylelint-config-gds/)
 
-A Ruby gem to document and distribute components for GOV.UK applications. It provides:
+govuk_publishing_components is a Ruby gem to document and distribute components for GOV.UK applications. It provides:
 
 - a shared library of components
 - helpers to generate component payloads
 - an application to preview components and provide guidance
 - [GOV.UK Design System](https://design-system.service.gov.uk/) styles and components (via [GOV.UK Frontend](https://github.com/alphagov/govuk-frontend))
 
-Components should be added to this gem if they are required in more than one application, otherwise they should be added to that application. All components should meet the same standards of browser and assistive technology support described in [GOV.UK Frontend](https://github.com/alphagov/govuk-frontend#browser-and-assistive-technology-support).
+Only add a component to this gem if it is required in more than one application. Please do not add application-specific components to govuk_publishing_components.
 
-## Technical documentation
-
-You can use the [GOV.UK Docker environment](https://github.com/alphagov/govuk-docker) or the local `startup.sh` script to run the app. Read the [guidance on local frontend development](https://docs.publishing.service.gov.uk/manual/local-frontend-development.html) to find out more about each approach, before you get started.
+All components should meet the accessibility standards for browser and assistive technology support described in [GOV.UK Frontend](https://github.com/alphagov/govuk-frontend#browser-and-assistive-technology-support).
 
-If you are using GOV.UK Docker, remember to combine it with the commands that follow. See the [GOV.UK Docker usage instructions](https://github.com/alphagov/govuk-docker#usage) for examples.
+## Technical documentation
 
-### Running the test suite
+### Run the test suite
 
 ```sh
 bundle install
 yarn install
 bundle exec rake
 ```
 
-To run JavaScript tests (only):
+### Run the JavaScript tests alone
+
+In browser:
 
 ```sh
-# run JS tests in browser
 yarn run jasmine:browser
+```
+
+On command line:
 
-# run JS tests on command line
+```sh
 yarn run jasmine:ci
 ```
 
-### Using the gem
+### Use the gem
 
 - [Install and use this gem](docs/install-and-use.md)
 - [Use a component in your application](docs/use-components.md)
 - [Test a branch of the gem](docs/test-a-branch-of-the-gem.md)
 
-### Managing the gem
+### Manage the gem
 
 - [Publish/release a new version of the gem](docs/publishing-to-rubygems.md)
 - [Keep this gem in sync with the Design System](docs/upgrade-govuk-frontend.md)
 - [Move a component from an application to the gem](docs/moving-components-upstream-into-this-gem.md)
 
-### Making components
+### Make a new component
 
 - [Generate a new component](docs/generate-a-new-component.md)
 - [Component conventions](docs/component_conventions.md)
 - [Component principles](docs/component_principles.md)
 
 ### Further documentation
 
-- [Testing a component](docs/testing-components.md)
-- [Component auditing](docs/auditing.md)
+- [Test a component](docs/testing-components.md)
+- [Audit a component](docs/auditing.md)
 - [Code documentation on rubydoc.info](http://www.rubydoc.info/gems/govuk_publishing_components)
 - [Our analytics approach](docs/analytics-ga4/analytics.md)
 
-More documentation can be found in the [docs directory](docs/).
+There is more documentation in the [docs directory](docs/).
 
 ## Licence