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/menu.h

@@ -902,7 +902,7 @@ public:
     bool IsEnabled(int id) const;
 
     /**
-        Inserts the given @a item at position 0, i.e. before all the other
+        Inserts the given @a item at position 0, i.e.\ before all the other
         existing items.
 
         @see Append(), Insert()
@@ -910,7 +910,7 @@ public:
     wxMenuItem* Prepend(wxMenuItem* item);
 
     /**
-        Inserts the given @a item at position 0, i.e. before all the other
+        Inserts the given @a item at position 0, i.e.\ before all the other
         existing items.
 
         @see Append(), Insert()