tmux, vim: enable true color support properly

.tmux.conf

@@ -5,6 +5,9 @@ set -g @plugin 'tmux-plugins/tmux-prefix-highlight'
 set -g @plugin 'odedlaz/tmux-onedark-theme'
 set -g @onedark_date_format "%d.%m.%y"
 
+set -g default-terminal "tmux-256color"
+set -ga terminal-overrides ",alacritty:Tc,*256col*:Tc"
+
 # Scroll History
 set -g history-limit 50000
 

.vimrc

@@ -31,11 +31,6 @@ set listchars=tab:>-,eol:$,trail:.,extends:#
 
 packadd! onedark.vim
 
-
-"Use 24-bit (true-color) mode in Vim/Neovim when outside tmux.
-"If you're using tmux version 2.2 or later, you can remove the outermost $TMUX check and use tmux's 24-bit color support
-"(see < http://sunaku.github.io/tmux-24bit-color.html#usage > for more information.)
-if (empty($TMUX))
 if (has("nvim"))
   "For Neovim 0.1.3 and 0.1.4 < https://github.com/neovim/neovim/pull/2198 >
   let $NVIM_TUI_ENABLE_TRUE_COLOR=1
@@ -48,7 +43,6 @@ if (empty($TMUX))
   let &t_8f = "\<Esc>[38;2;%lu;%lu;%lum"
   let &t_8b = "\<Esc>[48;2;%lu;%lu;%lum"
 endif
-endif
 
 syntax on
 let g:onedark_termcolors=16