Delete duplicated show-hide-content.js
Delete duplicated show-hide-content.js

This was added to the govuk_frontend_toolkit here: and was added to
govuk_elements when the toolkit was updated to version 4.18.0

https://github.com/alphagov/govuk_frontend_toolkit/blob/master/CHANGELOG
.md

alphagov/govuk_elements,alphagov/govuk_elements,alphagov/govuk_elements,alphagov/govuk_elements