Make the change

Open the file listed in the issue and update the documentation.
See “Ways to contribute” for examples.

Analyzing and Generating API Docs

Running this command from the root directory analyzes
and generates the documentation. This command can
take up to 20 minutes to complete, so double
check your changes first. If you want, you can also
analyze snippets directly.

To view the generated docs, open dev/docs/doc/api/index.html.

Note:
  Flutter API docs cannot be generated on Windows.
  If you are using Windows, you may need to download
  the Linux version of the SDK and use the
  Windows Subsystem for Linux.

For more information, see the Dartdoc Generation README.

Commit the change

Modify the documentation and commit the change:

b update-builder-widget
git add

A
git commit

m