Use "GTK+" where applicable in the manual

* doc/emacs/display.texi (Standard Faces, Standard Faces):
* doc/emacs/emacs.texi (Top):
* doc/emacs/files.texi (Visiting):
* doc/emacs/frames.texi (Scroll Bars):
* doc/emacs/xresources.texi: Use "GTK+" where applicable.

doc/emacs/display.texi

@@ -656,8 +656,8 @@ This face is used to highlight lazy matches for Isearch and Query
 Replace (matches other than the current one).
 @item region
 This face is used for displaying an active region (@pxref{Mark}).
-When Emacs is built with GTK support, its colors are taken from the
+When Emacs is built with GTK+ support, its colors are taken from the
-current GTK theme.
+current GTK+ theme.
 @item secondary-selection
 This face is used for displaying a secondary X selection (@pxref{Secondary
 Selection}).
@@ -741,7 +741,7 @@ The @code{:background} attribute of this face specifies the color of
 the text cursor.  @xref{Cursor Display}.
 @item tooltip
 This face is used for tooltip text.  By default, if Emacs is built
-with GTK support, tooltips are drawn via GTK and this face has no
+with GTK+ support, tooltips are drawn via GTK+ and this face has no
 effect.  @xref{Tooltips}.
 @item mouse
 This face determines the color of the mouse pointer.

doc/emacs/emacs.texi

@@ -1222,8 +1222,8 @@ GTK resources
 
 * GTK Resource Basics::   Basic usage of GTK+ resources.
 * GTK Widget Names::      How GTK+ widgets are named.
-* GTK Names in Emacs::    GTK widgets used by Emacs.
+* GTK Names in Emacs::    GTK+ widgets used by Emacs.
-* GTK styles::            What can be customized in a GTK widget.
+* GTK styles::            What can be customized in a GTK+ widget.
 
 Emacs and macOS / GNUstep
 

doc/emacs/files.texi

@@ -281,7 +281,7 @@ files.  Firstly, when Emacs is built with a suitable GUI toolkit,
 commands invoked with the mouse (by clicking on the menu bar or tool
 bar) use the toolkit's standard file selection dialog instead of
 prompting for the file name in the minibuffer.  On GNU/Linux and Unix
-platforms, Emacs does this when built with GTK, LessTif, and Motif
+platforms, Emacs does this when built with GTK+, LessTif, and Motif
 toolkits; on MS-Windows and Mac, the GUI version does that by default.
 For information on how to customize this, see @ref{Dialog Boxes}.
 

doc/emacs/frames.texi

@@ -1001,9 +1001,9 @@ when the entire buffer is visible.
 
 @cindex @code{scroll-bar} face
   The visual appearance of the scroll bars is controlled by the
-@code{scroll-bar} face.  (Some toolkits, such as GTK and MS-Windows,
+@code{scroll-bar} face.  (Some toolkits, such as GTK+ and MS-Windows,
 ignore this face; the scroll-bar appearance there can only be
-customized system-wide, for GTK @pxref{GTK resources}).
+customized system-wide, for GTK+ @pxref{GTK resources}).
 
 @cindex vertical border
   On graphical frames, vertical scroll bars implicitly serve to separate

doc/emacs/xresources.texi

@@ -12,10 +12,10 @@ resources, as is usual for programs that use X.
 graphical widgets, such as the menu-bar, scroll-bar, and dialog boxes,
 is determined by
 @ifnottex
-GTK resources, which we will also describe.
+GTK+ resources, which we will also describe.
 @end ifnottex
 @iftex
-GTK resources.
+GTK+ resources.
 @end iftex
 When Emacs is built without GTK+ support, the appearance of these
 widgets is determined by additional X resources.
@@ -28,7 +28,7 @@ system registry (@pxref{MS-Windows Registry}).
 * Table of Resources::  Table of specific X resources that affect Emacs.
 * Lucid Resources::     X resources for Lucid menus.
 * Motif Resources::     X resources for Motif and LessTif menus.
-* GTK resources::       Resources for GTK widgets.
+* GTK resources::       Resources for GTK+ widgets.
 @end menu
 
 @node Resources
@@ -515,7 +515,7 @@ The color for the border shadow, on the top and the left.
 @node GTK resources
 @appendixsec GTK resources
 @cindex GTK+ resources
-@cindex resource files for GTK
+@cindex resource files for GTK+
 @cindex @file{~/.gtkrc-2.0} file
 @cindex @file{~/.emacs.d/gtkrc} file
 
@@ -530,7 +530,7 @@ resources are specified in either the file @file{~/.emacs.d/gtkrc}
 (for Emacs-specific GTK+ resources), or @file{~/.gtkrc-2.0} (for
 general GTK+ resources).  We recommend using @file{~/.emacs.d/gtkrc},
 since GTK+ seems to ignore @file{~/.gtkrc-2.0} when running GConf with
-GNOME@.  Note, however, that some GTK themes may override
+GNOME@.  Note, however, that some GTK+ themes may override
 customizations in @file{~/.emacs.d/gtkrc}; there is nothing we can do
 about this.  GTK+ resources do not affect aspects of Emacs unrelated
 to GTK+ widgets, such as fonts and colors in the main Emacs window;
@@ -553,8 +553,8 @@ system, see
 @menu
 * GTK Resource Basics::   Basic usage of GTK+ resources.
 * GTK Widget Names::      How GTK+ widgets are named.
-* GTK Names in Emacs::    GTK widgets used by Emacs.
+* GTK Names in Emacs::    GTK+ widgets used by Emacs.
-* GTK styles::            What can be customized in a GTK widget.
+* GTK styles::            What can be customized in a GTK+ widget.
 @end menu
 
 @node GTK Resource Basics
@@ -617,7 +617,7 @@ widget "*verticalScrollBar*" style "scroll"
 
 @node GTK Widget Names
 @appendixsubsec GTK widget names
-@cindex GTK widget names
+@cindex GTK+ widget names
 
   A GTK+ widget is specified by a @dfn{widget name} and a @dfn{widget
 class}.  The widget name refers to a specific widget
@@ -662,8 +662,8 @@ widget "*" style "my_style"
 
 @node GTK Names in Emacs
 @appendixsubsec GTK Widget Names in Emacs
-@cindex GTK widget names in Emacs
+@cindex GTK+ widget names in Emacs
-@cindex GTK widget classes
+@cindex GTK+ widget classes
 
   The GTK+ widgets used by an Emacs frame are listed below:
 
@@ -726,7 +726,7 @@ widget_class "*Menu*" style "my_menu_style"
 
 @node GTK styles
 @appendixsubsec GTK styles
-@cindex GTK styles
+@cindex GTK+ styles
 
   Here is an example of two GTK+ style declarations: