tmux: make pagers not blank the screen

etc/tmux.conf

@@ -4,7 +4,7 @@
 
 # prefix = Ctrl+A, double that to send it literally (like screen)
 unbind C-b
-set -g prefix C-a
+set-option -g prefix C-a
 bind C-a send-prefix
 
 # Shift+S to type into all panes at once
@@ -23,14 +23,17 @@ bind-key - split-window -v
 # └─────────────┘
 
 # mouse (scrolling, selection)
-set -g mouse on
+set-option -g mouse on
 
 # I got room!
-set -g history-limit 100000
+set-option -g history-limit 100000
 
 # rename windows using escape sequences
 set-window-option -g automatic-rename off
-set -g allow-rename on
+set-option -g allow-rename on
+
+# so pagers don't blank the screen
+set-option -g alternate-screen off
 
 # ┌──────────────────────────────────────────────────────┐
 # │ Gruvbox ^^ from https://github.com/egel/tmux-gruvbox │