Pass non-primitive types by const reference instead of value.

No real changes, just avoid the unnecessary copying and also make the
signatures more consistent by adding the apparently forgotten "&" in a couple
of places.

See #15893.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@75657 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/propgrid/propgrid.h

@@ -1692,7 +1692,7 @@ public:
         @param text
             Initial text value of created wxTextCtrl.
     */
-    void SetupTextCtrlValue( const wxString text ) { m_prevTcValue = text; }
+    void SetupTextCtrlValue( const wxString& text ) { m_prevTcValue = text; }
 
     /**
         Unfocuses or closes editor if one was open, but does not deselect