Add alacritty to list of recognized terminals for Bash window titling

dotfiles/config/bashum/post.bashrc

     #
     echo -n '__bashum__save_rv $?;'
     case "$TERM" in
-        xterm*|rxvt*|screen*)
+        xterm*|rxvt*|screen*|alacritty)
             echo -n 'echo -ne "\033]0;'
             echo -n   "$(__bashum__mkicon) "
             echo -n   '$(__bashum__lastrv)'