main/nano: upgrade to 5.3

from the changelog:

Nano no longer by default tries using libmagic to determine the type of a file (when neither filename nor first line gave a clue), because in most cases it is a waste of time. It requires using the option --magic or -! or 'set magic' to make nano try libmagic.

so, maybe we could drop file-dev from makedepends and go for a smaller package.