Fix modes code to support keycodes patch

Merge remote-tracking branch 'modes/v0.5/modes' into v0.6-a/keycodes-modes

use keycodes instead of keysyms

inspiration: https://codeberg.org/dwl/dwl-patches/wiki/keycodes

Fix rule examples; minimize newbie surprises

Make example rules be actual EXAMPLES.
Now newcomers should not have to ask, "When I start firefox, nothing
happens. What is going on?"

Also clarified a minor typo and a consistency in spacing.

implement modes

like sway/river modes

turn on -Wfloat-conversion

restore and respect rootcolor

add a note about not removing the default rule

Closes: https://codeberg.org/dwl/dwl/issues/527

add a comment about chvt keybindings

Closes: https://github.com/djpohly/dwl/issues/427

Merge remote-tracking branch 'upstream/main' into wlroots-next

Revert "just add define"

I'm going to make some changes in the config file anyway

This reverts commit e5367753bb90add013ee5d170a110064298ac2c4.

add [-d] flag to enable debug logging

make the borders red borders for urgent clients

iirc this is the same behavior of dwm

use the same border colors as dwm

add missing url about the COLOR macro

add macro to configure colors

Closes: https://github.com/djpohly/dwl/issues/466

Merge remote-tracking branch 'upstream/main' into wlroots-next

just add define

tagcount should have been a #define

Merge remote-tracking branch 'upstream/main' into wlroots-next