Update CHANGELOG with a working workaroud for removal of govuk-if-ie8

[romaricpascal]

Mixins that accept content require @content, otherwise Sass fails to compile so the example need updating.

Release notes and PR content have already been updated.

Closes #4556

[github-actions]

📋 Stats

File sizes

File	Size
dist/govuk-frontend-development.min.css	113.72 KiB
dist/govuk-frontend-development.min.js	38.54 KiB
packages/govuk-frontend/dist/govuk/all.bundle.js	78.3 KiB
packages/govuk-frontend/dist/govuk/all.bundle.mjs	73.58 KiB
packages/govuk-frontend/dist/govuk/all.mjs	3.86 KiB
packages/govuk-frontend/dist/govuk/govuk-frontend-component.mjs	359 B
packages/govuk-frontend/dist/govuk/govuk-frontend.min.css	113.7 KiB
packages/govuk-frontend/dist/govuk/govuk-frontend.min.js	38.53 KiB
packages/govuk-frontend/dist/govuk/i18n.mjs	5.38 KiB

Modules

File	Size
all.mjs	69.9 KiB
components/accordion/accordion.mjs	21.67 KiB
components/button/button.mjs	4.7 KiB
components/character-count/character-count.mjs	21.24 KiB
components/checkboxes/checkboxes.mjs	5.83 KiB
components/error-summary/error-summary.mjs	6.09 KiB
components/exit-this-page/exit-this-page.mjs	16.08 KiB
components/header/header.mjs	3.9 KiB
components/notification-banner/notification-banner.mjs	4.54 KiB
components/radios/radios.mjs	4.83 KiB
components/skip-link/skip-link.mjs	4.3 KiB
components/tabs/tabs.mjs	9.66 KiB

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