Rearrange TUI data window code

Rearrange TUI data window code

An earlier patch caused tui-windata.h to be essentially empty.  And,
other earlier patches implemented TUI data window methods in any spot
that happened to be convenient at the time.

This patch rearranges all the data window code to be somewhat more
organized.  It moves tui_data_window to tui-regs.h, and moves the
implementation of all methods to tui-regs.c.  It then removes
tui-windata.h and tui-windata.c.

It also removes the "structuring" comments from tui-regs.c; these are
not the usual gdb style, and were out of date anyhow.  Finally, it
moves _initialize_tui_regs to the end of the file, per the usual gdb
convention.

gdb/ChangeLog
2019-07-17  Tom Tromey  <tom@tromey.com>

	* tui/tui.c: Update.
	* tui/tui-wingeneral.c (tui_data_window::refresh_window): Move to
	tui-regs.c.
	* tui/tui-windata.h: Remove file.
	* tui/tui-windata.c: Remove file.
	* tui/tui-win.c (tui_data_window::set_new_height)
	(tui_data_window::do_make_visible_with_new_height): Move to
	tui-regs.c.
	* tui/tui-regs.h (struct tui_data_window): Move from tui-data.h.
	* tui/tui-regs.c: Remove "structuring" comments.
	(tui_data_window::first_data_item_displayed)
	(tui_data_window::delete_data_content_windows)
	(tui_data_window::erase_data_content)
	(tui_data_window::display_all_data)
	(tui_data_window::refresh_all)
	(tui_data_window::do_scroll_vertical)
	(tui_data_window::clear_detail, tui_data_window::set_new_height)
	(tui_data_window::do_make_visible_with_new_height)
	(tui_data_window::refresh_window): Move from elsewhere.
	(_initialize_tui_regs): Move to end of file.
	* tui/tui-layout.c: Update.
	* tui/tui-hooks.c: Update.
	* tui/tui-data.h (struct tui_data_window): Move to tui-regs.h.
	* tui/tui-data.c (tui_data_window::clear_detail): Move to
	tui-regs.c.
	* Makefile.in (SUBDIR_TUI_SRCS): Remove tui-windata.c.