doc/misc/{gnus.texi,gnus-faq.texi}: Add link to EWW manual

* gnus.texi (HTML): Update section so that it mentions shr and w3m.
Also link the full EWW manual that explains more on shr, too.

* gnus-faq.texi (FAQ 4 - Reading messages, FAQ 4-16): Add Q&A on how to
increase contrast when displaying HTML mail with shr.
Improve inhibiting of implied frame resizes.

* frames.texi (Size and Position): Rewrite description of
`frame-inhibit-implied-resize'.
* cus-start.el (frame-resize-pixelwise): Fix group.
(frame-inhibit-implied-resize): Add entry.
* dispnew.c (change_frame_size_1): Fix call of
adjust_frame_size.
* frame.c (Qsize, Qframe_position, Qframe_outer_size)
(Qframe_inner_size, Qexternal_border_size, Qtitle_height)
(Qmenu_bar_external, Qmenu_bar_size, Qtool_bar_external)
(Qtool_bar_size): New constants.
(frame_inhibit_resize, adjust_frame_size): New argument to
handle case where frame_inhibit_implied_resize is a list.
(Fmake_terminal_frame, Fset_frame_height, Fset_frame_width)
(Fset_frame_size, x_set_left_fringe, x_set_right_fringe)
(x_set_right_divider_width, x_set_bottom_divider_width)
(x_set_vertical_scroll_bars, x_set_horizontal_scroll_bars)
(x_set_scroll_bar_width, x_set_scroll_bar_height): Update
callers.
(frame-inhibit-implied-resize): Rewrite doc-string.
* frame.h (frame_inhibit_resize, adjust_frame_size): Fix
external declarations.
(Qframe_position, Qframe_outer_size)
(Qframe_inner_size, Qexternal_border_size, Qtitle_height)
(Qmenu_bar_external, Qmenu_bar_size, Qtool_bar_external)
(Qtool_bar_size): Extern them.
* gtkutil.c (FRAME_TOTAL_PIXEL_HEIGHT, FRAME_TOTAL_PIXEL_WIDTH)
(xg_height_or_width_changed): Remove.
(xg_frame_set_char_size): Adjust adjust_frame_size calls.
(menubar_map_cb, xg_update_frame_menubar, free_frame_menubar)
(tb_size_cb, update_frame_tool_bar, free_frame_tool_bar)
(xg_change_toolbar_position): Call adjust_frame_size directly.
* nsfns.m (x_set_internal_border_width, Fx_create_frame): Fix
calls of adjust_frame_size.
* w32fns.c (x_set_internal_border_width, x_set_menu_bar_lines)
(Fx_create_frame, x_create_tip_frame): Adjust adjust_frame_size
calls.
(x_set_tool_bar_lines, x_change_tool_bar_height): Make sure that
frame can get resized when tool-bar-lines parameter changes from
or to zero.
(Fw32_frame_menu_bar_size): Return fourth value.
(Fw32_frame_rect): Block input around system calls
(Fx_frame_geometry): New function.
* w32menu.c (set_frame_menubar): Adjust adjust_frame_size call.
* w32term.c (x_new_font): Adjust adjust_frame_size call.
* widget.c (EmacsFrameSetCharSize): Adjust frame_inhibit_resize
call.
* window.c (Fset_window_configuration): Adjust adjust_frame_size
call.
* xfns.c (x_set_menu_bar_lines, x_set_internal_border_width)
(Fx_create_frame): Adjust adjust_frame_size calls.
(x_set_tool_bar_lines, x_change_tool_bar_height): Make sure that
frame can get resized when tool-bar-lines parameter changes from
or to zero.
(Fx_frame_geometry): New function.
* xmenu.c (update_frame_menubar): On Lucid call
adjust_frame_size with one pixel less height to avoid that
repeatedly adding/removing the menu bar grows the frame.
(free_frame_menubar): On Motif arrange to optionally preserve
the old frame height when removing the menu bar.
* xterm.c (x_new_font): Adjust adjust_frame_size call.