With Emacs 27 we are using the new built-in
display-fill-column-indicator mode. It does not have issues with
web-mode like fci-mode from the fill-column-indicator package does.
This module wraps around the fill-column-indicator and it's
fci-mode. This will enable easy switch-over to Emacs 27's native
display-fill-column-indicator feature.
- Switch from highlight-indentation package to highlight-indent-guides.
- Activate visual indentation in a prog-mode hook, rather than doing
within each individual major mode. It was already done within all
major modes based on prog-mode anyway.
- Add new siren-display-indetation module and function as a central way
to enable visual indetation guides. This makes switching the
underlying package at some point in the future much easier.
