tmux: Enter copy-mode w/o prefix on PageUp

Enter copy-mode and scroll one page up directly with PageUp without the
need of the prefix. This binding exists per default already in the
prefix keytable.

.config/tmux/tmux.conf

@@ -34,6 +34,10 @@ bind-key -T prefix F resize-pane -Z
 # Automatically renumber windows when closing one
 set -g renumber-windows on
 
+# Enter copy-mode and scroll one page up directly with PageUp without the need
+# of the prefix. (Exists already per default with prefix)
+bind-key -n PPage copy-mode -u
+
 # Vim-bindings
 
 # Enter copy-mode with Escape