No changes, just remove unused part of expression.

We don't do anything with the result of inserting the watch in
fswatchercmn.cpp.

Closes #15027.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73464 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/fswatchercmn.cpp

@@ -130,7 +130,7 @@ wxFileSystemWatcherBase::AddAny(const wxFileName& path,
     if ( it == m_watches.end() )
     {
         wxFSWatchInfoMap::value_type val(canonical, watch);
-        m_watches.insert(val).second;
+        m_watches.insert(val);
     }
     else
     {