[LyX/master] Add comment.

[Richard Heck]

commit 2928afbd01b58cfe639b8390081c9dfcd4fb3a0f
Author: Juergen Spitzmueller <sp...@lyx.org>
Date:   Mon Apr 7 08:46:35 2014 +0200

    Add comment.

diff --git a/src/Layout.h b/src/Layout.h
index 913546f..05f6cbd 100644
--- a/src/Layout.h
+++ b/src/Layout.h
@@ -108,13 +108,18 @@ public:
        ///
        typedef std::map<std::string, latexarg> LaTeXArgMap;
        ///
-       LaTeXArgMap args() const;
-       ///
        LaTeXArgMap const & latexargs() const { return latexargs_; }
        ///
        LaTeXArgMap const & postcommandargs() const { return postcommandargs_; }
        ///
        LaTeXArgMap const & itemargs() const { return itemargs_; }
+       /// Returns latexargs() + postcommandargs() + itemargs().
+       /// But note that it returns a *copy*, not a reference, so do not do
+       /// anything like:
+       ///   Layout::LaTeXArgMap it = args().begin();
+       ///   Layout::LaTeXArgMap en = args().end();
+       /// Those are iterators for different containers.
+       LaTeXArgMap args() const;
        ///
        int optArgs() const;
        ///