Add some more tests for recent stuff.

regress/format-variables.sh

@@ -71,7 +71,10 @@ cursor_very_visible
 cursor_x
 cursor_y
 history_all_bytes
+history_added
 history_bytes
+history_collected
+history_generation
 history_limit
 history_size
 host
@@ -103,6 +106,11 @@ pane_at_right
 pane_at_top
 pane_bg
 pane_bottom
+pane_command_duration
+pane_command_end_time
+pane_command_running
+pane_command_start_time
+pane_command_status
 pane_current_command
 pane_current_path
 pane_dead
@@ -120,16 +128,21 @@ pane_index
 pane_input_off
 pane_key_mode
 pane_last
+pane_last_output_time
+pane_last_prompt_time
 pane_left
 pane_marked
 pane_marked_set
+pane_modal_flag
 pane_mode
+pane_output_generation
 pane_path
 pane_pb_progress
 pane_pb_state
 pane_pid
 pane_pipe
 pane_pipe_pid
+pane_private_modes
 pane_right
 pane_search_string
 pane_start_command
@@ -141,6 +154,8 @@ pane_title
 pane_top
 pane_tty
 pane_unseen_changes
+pane_unzoomed_height
+pane_unzoomed_width
 pane_width
 pane_x
 pane_y
@@ -206,7 +221,10 @@ window_layout
 window_linked
 window_linked_sessions
 window_linked_sessions_list
+window_manual_height
+window_manual_width
 window_marked_flag
+window_modal_pane
 window_name
 window_offset_x
 window_offset_y