wxwidgets.cfg add some missing configuration for wxPropertyGrid (#8087)

This pull request adds support for additional methods in the `wxwidgets`
configuration file to improve property grid functionality and access.
The most notable changes are the addition of new function definitions
related to property value retrieval and grid access.

New property retrieval functions:

* Added definitions for `wxPGProperty::GetValue` and
`wxPGProperty::DoGetValue`, enabling retrieval of property values as
`wxVariant` objects.

Property grid access:

* Added definition for `wxPropertyGridManager::GetGrid`, allowing direct
access to the underlying `wxPropertyGrid` from a
`wxPropertyGridManager`.

Author: orbitcowboy

cfg/wxwidgets.cfg

@@ -7253,6 +7253,15 @@
     <returnValue type="wxString"/>
     <warn severity="style">This function is deprecated, use 'wxPGProperty::GetValueAsString()' instead.</warn>
   </function>
+  <!-- virtual wxVariant wxPGProperty::DoGetValue(void) const -->
+  <!--         wxVariant wxPGProperty::GetValue(void) const   -->
+  <function name="wxPGProperty::GetValue,wxPGProperty::DoGetValue">
+    <noreturn>false</noreturn>
+    <leak-ignore/>
+    <use-retval/>
+    <const/>
+    <returnValue type="wxVariant"/>
+  </function>
   <!-- wxString wxPGPropertyFlags::wxPGProperty::GetValueAsStringWithCheck( wxPGPropValFormatFlags flags = wxPGPropValFormatFlags::Null ) const -->
   <!-- wxString wxPGProperty::GetValueAsString( wxPGPropValFormatFlags flags = wxPGPropValFormatFlags::Null ) const -->
   <function name="wxPGPropertyFlags::wxPGProperty::GetValueAsStringWithCheck,wxPGProperty::GetValueAsString">
@@ -11384,6 +11393,12 @@
       <not-bool/>
     </arg>
   </function>
+  <!-- wxPropertyGrid* wxPropertyGridManager::GetGrid(void) -->
+  <function name="wxPropertyGridManager::GetGrid">
+    <noreturn>false</noreturn>
+    <leak-ignore/>
+    <returnValue type="wxPropertyGrid *"/>
+  </function>
   <!-- wxPGProperty * wxPropertyGridInterface::Append( wxPGProperty * property ) -->
   <!-- wxPGProperty * wxPropertyGridManager::Append( wxPGProperty * property ) -->
   <function name="wxPropertyGridInterface::Append,wxPropertyGridManager::Append">