feat: Increase line width to 80 characters

[juliusknorr]

📝 Summary

After discussion with designers we wanted to slightly increase the line width of text documents. This is basically the same width as talk uses now for messages which is 80 character width.

Browser support for the ch unit seems sufficient: https://caniuse.com/ch-unit

🖼️ Screenshots

🏚️ Before	🏡 After

🏁 Checklist

• Code is properly formatted (npm run lint / npm run stylelint / composer run cs:check)
• Sign-off message is added to all commits
• Tests (unit, integration and/or end-to-end) passing and the changes are covered with tests
• Documentation (README or documentation) has been updated or is not required

[marcoambrosini]

Hmm I think talk has already slightly decreased that, cc @Antreesy

[juliusknorr]

Talks seems to be using https://github.com/nextcloud/spreed/blob/81c8bfca584c3cbb1d8aa4a716a2f19148bb7059/src/assets/variables.scss#L13 (which ends up at 750px with 15px font size), 80ch end up being 734px in text

[marcoambrosini]

Sgtm then!

[max-nextcloud]

Thanks!

[Antreesy]

Just a note to consider: width may vary a bit depending on a font. so for OpenDyslexic 80ch is ~780px, for default on Win11 ~650px

[bekuno]

I propose to backport this small change.