Make Pcbnew search about zone names, fixes #6951

I put zones in "other text items" category of searching as I thought it
would be the appropriate one.

Fixes https://gitlab.com/kicad/code/kicad/issues/6951

pcbnew/dialogs/dialog_find.cpp

@@ -257,6 +257,15 @@ void DIALOG_FIND::search( bool aDirection )
                         m_hitList.push_back( textItem );
                     }
                 }
+
+                for( BOARD_ITEM* item : m_frame->GetBoard()->Zones() )
+                {
+                    ZONE* zoneItem = dynamic_cast<ZONE*>( item );
+                    if( zoneItem && zoneItem->Matches( m_frame->GetFindReplaceData(), nullptr ) )
+                    {
+                        m_hitList.push_back( zoneItem );
+                    }
+                }
             }
         }
 

pcbnew/zone.h

@@ -131,6 +131,11 @@ public:
     wxString GetZoneName() const { return m_zoneName; }
     void SetZoneName( const wxString& aName ) { m_zoneName = aName; }
 
+    bool Matches( wxFindReplaceData& aSearchData, void* aAuxData ) override
+    {
+        return BOARD_ITEM::Matches( GetZoneName(), aSearchData );
+    }
+
     /**
      * Function GetBoundingBox (virtual)
      * @return an EDA_RECT that is the bounding box of the zone outline