Fix premature truncation of brief descriptions in Doxygen comments.

Don't end the brief description at the first period if it's a period which is
part of "i.e." or "e.g.": escape the space following it to prevent Doxygen
from recognizing it as an end of sentence.

See #14866.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73084 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/treectrl.h

@@ -726,7 +726,7 @@ public:
     virtual bool IsBold(const wxTreeItemId& item) const;
 
     /**
-        Returns @true if the control is empty (i.e. has no items, even no root
+        Returns @true if the control is empty (i.e.\ has no items, even no root
         one).
     */
     bool IsEmpty() const;