Add GtkCenterLayout to the docs

docs/reference/gtk/gtk4-docs.xml

@@ -117,9 +117,10 @@
       <xi:include href="xml/gtklayoutchild.xml" />
       <xi:include href="xml/gtkbinlayout.xml" />
       <xi:include href="xml/gtkboxlayout.xml" />
-      <xi:include href="xml/gtkcustomlayout.xml" />
+      <xi:include href="xml/gtkcenterlayout.xml" />
       <xi:include href="xml/gtkfixedlayout.xml" />
       <xi:include href="xml/gtkgridlayout.xml" />
+      <xi:include href="xml/gtkcustomlayout.xml" />
       <xi:include href="xml/gtkconstraintlayout.xml" />
       <xi:include href="xml/gtkconstraint.xml" />
       <xi:include href="xml/gtkconstraintguide.xml" />

docs/reference/gtk/gtk4-sections.txt

@@ -6639,6 +6639,27 @@ GTK_TYPE_BOX_LAYOUT
 gtk_box_layout_get_type
 </SECTION>
 
+<SECTION>
+<FILE>gtkcenterlayout</FILE>
+GtkCenterLayout
+
+gtk_center_layout_new
+gtk_center_layout_set_orientation
+gtk_center_layout_get_orientation
+gtk_center_layout_set_baseline_position
+gtk_center_layout_get_baseline_position
+gtk_center_layout_set_start_widget
+gtk_center_layout_get_start_widget
+gtk_center_layout_set_center_widget
+gtk_center_layout_get_center_widget
+gtk_center_layout_set_end_widget
+gtk_center_layout_get_end_widget
+
+<SUBSECTION Standard>
+GTK_TYPE_CENTER_LAYOUT
+gtk_center_layout_get_type
+</SECTION>
+
 <SECTION>
 <FILE>gtkcustomlayout</FILE>
 GtkCustomLayout

docs/reference/gtk/gtk4.types.in

@@ -41,6 +41,7 @@ gtk_cell_renderer_spinner_get_type
 gtk_cell_renderer_text_get_type
 gtk_cell_renderer_toggle_get_type
 gtk_cell_view_get_type
+gtk_center_layout_get_type
 gtk_check_button_get_type
 gtk_color_button_get_type
 gtk_color_chooser_get_type