Toggle for plaintext wrapping.

[max-nextcloud]

When using plain text files users should be able to decide if they want lines to be wrapped or not. This should be implemented using a toggle. The toggle state could be remembered in the browser storage.

Either wrapping or not wrapping will not work for everyone or every file type / content. Having a toggle is quite common for a text editors. Originally posted by @juliushaertl in https://github.com/nextcloud/text/issues/1407#issuecomment-1093018583

We also do not have a menubar in plaintext view so the ui is fairly simple anyway.