- Make use of use-package's :bind option whenever possible.
- Make use of use-package's :hook option whenever possible.
- Rename and move all mode setup functions into use-package's :init
step.
- Other minor misc fixes and tweaks to a few modules.
All siren modules lazy-load if they can, so there's no need to
lazy-require a siren module.
Also this avoids the annoyance of the first time you use a feature
it triggers a package install from melpa. All such things should
happen as part of Emacs startup.
