gtk.cfg: Add more details for g_print() and g_printerr()

Reference:
https://developer.gnome.org/glib/stable/glib-Warnings-and-Assertions.html#g-print

cfg/gtk.cfg

@@ -2307,13 +2307,19 @@
     <leak-ignore/>
     <noreturn>false</noreturn>
   </function>
-  <function name="g_print">
-    <leak-ignore/>
-    <noreturn>false</noreturn>
-  </function>
-  <function name="g_printerr">
+  <!-- void g_print (const gchar *format, ...); -->
+  <!-- void g_printerr (const gchar *format, ...); -->
+  <function name="g_print,g_printerr">
     <leak-ignore/>
     <noreturn>false</noreturn>
+    <returnValue type="void"/>
+    <formatstr/>
+    <arg nr="1">
+      <not-null/>
+      <not-uninit/>
+      <formatstr/>
+      <strz/>
+    </arg>
   </function>
   <function name="g_printf">
     <leak-ignore/>

test/cfg/gtk.c

@@ -8,6 +8,8 @@
 //
 
 #include <gtk/gtk.h>
+#include <glib.h>
+
 
 void validCode(int argInt)
 {
@@ -36,6 +38,10 @@ void validCode(int argInt)
     int i = GPOINTER_TO_INT(p);
     // cppcheck-suppress knownConditionTrueFalse
     if (i == 1) {}
+
+    g_print("test");
+    g_print("%d", 1);
+    g_printerr("err");
 }
 
 void g_malloc_test()
@@ -56,3 +62,11 @@ void g_assert_test()
     // cppcheck-suppress assignmentInAssert
     g_assert(a = 5);
 }
+
+void g_print_test()
+{
+    // cppcheck-suppress invalidPrintfArgType_uint
+    g_print("%u", -1);
+    // cppcheck-suppress invalidPrintfArgType_uint
+    g_printerr("%x", "a");
+}