nvim: after/ftplugin/rust: Add a mapping to open cargo docs
fish: Update cargo doc open command

Now that we set BROWSER correctly, we need not set this here.
fish: Unset and set BROWSER

For some reason, BROWSER always gets set to firefox instead of
firefox-wayland which is our own desktop file for starting firefox
in wayland.

Setting the systemd environment variables or using the env in desktop
file has not helped.
i3: Clean up configuration

Purge all left over settings from manjaro days.
fish: Start sway if running from tty1

sway seems to not start at all when using lightdm to login. We disabled
lightdm and now just use the login shell to start sway. sway never
recommended login managers so this was long due anyways.

See https://github.com/swaywm/sway/wiki#login-managers.
sway: Fix import of environment variables

See https://wiki.archlinux.org/title/Sway#Manage_Sway-specific_daemons_with_systemd.
sway: Do not start kanshi

We do not use dual monitor setup at the moment so do not start kanshi.
sway: Update wallpaper
nvim: keymappings: Drop all key mappings for tags

We do not use tags anymore so drop those. Especially never used the
preview tag mappings.
nvim: colors/yolokai: Fix git diff highlight group

The previous setting resulted in atrocious highlighting in diffs.
nvim: autoload/git: Fix the arguments to difftool
nvim: plugins: Drop diffview

Something as basic as :DiffviewOpen <commit> does not work.
nvim: after/ftplugin/dirvish: Add key mapping to yank file path
git: Continue listing the history of a file beyond renames
nvim: init: Disable virtual text for all diagnostics

They frequently get clipped beyond the window border due to being too
long and are not that helpful.

While at it, use our own preferable default sane options for the rest.
nvim: keymappings: Update to use the new diagnostic API

While at it, switch the key mapping to use the more convenient one for
line diagnostic.
nvim: Update packer
nvim: lsp: Enable LSP document highlight
nvim: yolokai: Add LSP highlight
paru: Add a configuration for paru

Pretty much a copy of paru.conf in the repo with CleanAfter and
FileManager set to nvim.