doc/concepts.tex: Missing blank line before subsection.

diff --git a/doc/concepts.tex b/doc/concepts.tex
index 1af615d..81f681b 100644 (file)
--- a/doc/concepts.tex
+++ b/doc/concepts.tex
@@ -273,6 +273,7 @@ to it in a slot.  (This will also help preserve binary compatibility, because
 the private structure can grow more members as needed.  See
 \xref{sec:fixme.compatibility} for more details.)
 
+
 \subsubsection{Vtables}