tmux: Support yy in copy-mode-vi

.config/tmux/tmux.conf

@@ -139,8 +139,13 @@ bind -T copy-mode-vi y \
 		send -X copy-pipe
 	} {
 		command-prompt -k -p (operator-pending) {
-			send -X begin-selection
+			# do line-wise yank on yy
-			send "%%"
+			if -F "#{==:%%,y}" {
+				send -X select-line
+			} {
+				send -X begin-selection
+				send "%%"
+			}
 			send -X copy-pipe
 		}
 	}