Post-installaion / Language support install: Suggest to install en_US always.

[steils]

Here: https://linuxmint-installation-guide.readthedocs.io/en/latest/locales.html

If user installs only non-English LSPs, some weird bugs and unexpected behaviour may occur. This maybe bugs in the software, yet I happened to encounter them. Nevertheless I suggest to add an advice for the user to always install "English / United States UTF-8" language support regardless of selected system localization.

[Jeremy7701]

If you are going to install "English", at least make sure that it is the variety of English that matches the users keyboard.