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/filefn.h

@@ -322,7 +322,7 @@ wxString wxPathOnly(const wxString& path);
 bool wxIsWild(const wxString& pattern);
 
 /**
-    Returns @true if the argument is an absolute filename, i.e. with a slash
+    Returns @true if the argument is an absolute filename, i.e.\ with a slash
     or drive name at the beginning.
 
     @header{wx/filefn.h}