[library-web] Add gtk4 to the developer docs

[Frederic Peters <fpeters src gnome org>]

commit 4b499d96772d319a4d32c557992f4ab6f130eba4
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Jan 1 17:13:42 2017 -0500

    Add gtk4 to the developer docs
    
    This adds entries for gsk4, gdk4 and gtk4.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=776692

 data/overlay.xml.in |   28 ++++++++++++++++++++++++++++
 1 files changed, 28 insertions(+), 0 deletions(-)
---
diff --git a/data/overlay.xml.in b/data/overlay.xml.in
index adf00e1..b051cea 100644
--- a/data/overlay.xml.in
+++ b/data/overlay.xml.in
@@ -163,6 +163,15 @@
       </_abstract>
       <extra-devel-releases>2.90</extra-devel-releases>
     </document>
+    <document doc_module="gsk4" channel="devel" weight="0.88">
+      <category>api-base</category>
+      <subsection>api-ui</subsection>
+      <_abstract>
+        An intermediate layer which isolates GTK+ from the details of the
+        OpenGL or Vulkan implementation.
+      </_abstract>
+      <extra-devel-releases>3.89</extra-devel-releases>
+    </document>
     <document doc_module="gdk2" channel="devel" weight="0.88">
       <category>api-base</category>
       <subsection>api-ui</subsection>
@@ -183,6 +192,15 @@
       </_abstract>
       <extra-devel-releases>2.90</extra-devel-releases>
     </document>
+    <document doc_module="gdk4" channel="devel" weight="0.88">
+      <category>api-base</category>
+      <subsection>api-ui</subsection>
+      <_abstract>
+        An intermediate layer which isolates GTK+ from the details of the
+        windowing system.
+      </_abstract>
+      <extra-devel-releases>3.89</extra-devel-releases>
+    </document>
     <document doc_module="gtk2" channel="devel" weight="0.87">
       <category>api-base</category>
       <subsection>api-ui</subsection>
@@ -206,6 +224,16 @@
       </_abstract>
       <extra-devel-releases>2.90</extra-devel-releases>
     </document>
+    <document doc_module="gtk4" channel="devel" weight="0.87">
+      <category>api-base</category>
+      <subsection>api-ui</subsection>
+      <_abstract>
+        GTK+ is the primary library used to construct user interfaces in GNOME
+        applications. It provides user interface controls and signal callbacks
+        to control user interfaces.
+      </_abstract>
+      <extra-devel-releases>3.89</extra-devel-releases>
+    </document>
     <document doc_module="libxml2" channel="devel" category="api" weight="0.86">
       <category>api-base</category>
       <new/>