docs: modules do not rely on models, services do (#17861)
docs: modules do not rely on models, services do (#17861)

services: provide some services for users, usually use
database (models) modules: provide some basic functions without
database, eg: code parser, etc The major difference is services use
database, while modules don’t.

Signed-off-by: singuliere <1a462a8e0b6ab96b81e2f02f0ff0d35811cc5bce@autistici.org>
go-gitea/gitea,go-gitea/gitea,go-gitea/gitea