Document wxListCtrl::FindItem() return value.

In particular mention that it returns -1 if no items were found.

Closes #11523.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62810 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/listctrl.h

@@ -257,6 +257,8 @@ public:
         beginning if start is @c -1. The string comparison is case insensitive.
 
         If @a partial is @true then this method will look for items which begin with @a str.
+
+        @return The next matching item if any or @c -1 (wxNOT_FOUND) otherwise.
     */
     long FindItem(long start, const wxString& str,
                   bool partial = false);
@@ -268,6 +270,8 @@ public:
         @beginWxPerlOnly
         In wxPerl this method is implemented as FindItemData(start, data).
         @endWxPerlOnly
+
+        @return The next matching item if any or @c -1 (wxNOT_FOUND) otherwise.
     */
     long FindItem(long start, wxUIntPtr data);
 
@@ -278,6 +282,8 @@ public:
         @beginWxPerlOnly
         In wxPerl this method is implemented as FindItemAtPos(start, pt, direction).
         @endWxPerlOnly
+
+        @return The next matching item if any or @c -1 (wxNOT_FOUND) otherwise.
     */
     long FindItem(long start, const wxPoint& pt, int direction);