Docker: How to install the php enchant extension

If I try to install the php enchant extension in the docker image php:8.1-fpm with

RUN docker-php-ext-install enchant

I get the following error:

E: Unable to locate package libenchant-2

You need to install the missing enchant library in the dockerfile yourself (along with your wanted spellcheck language, in my case Swiss German):

RUN apt-get install -y libenchant-2-2 libenchant-2-dev aspell-de hunspell-de-ch \
   && docker-php-ext-install enchant