Remove unused 'c' (saturnin-clip) binding to avoid conflict

...planning to re-use it for saturnin-xuris -c (like b and Shift+b but
with interactive handler choice).

dotfiles/i3/config

 bindsym $mod+Ctrl+Shift+b   exec "saturnin uris -1 | saturnin xuris -c"
 bindsym $mod+i              exec "saturnin menu uris"
 bindsym $mod+Shift+i        exec "saturnin menu www_hist"
-bindsym $mod+c              exec "saturnin clip save"
-bindsym $mod+Shift+c        exec "saturnin clip load"
 bindsym $mod+Shift+f        exec thunar
 bindsym $mod+Shift+o        exec "urxvt -e mocp"
 bindsym $mod+d              exec xbacklight -dec 50