Update release notes

doc/ReleaseNotes/develop.tex

@@ -3,12 +3,12 @@
 
 	\item \currentmodflowversion
 
-	%\underline{NEW FUNCTIONALITY}
-	%\begin{itemize}
-	%	\item xxx
+	\underline{NEW FUNCTIONALITY}
+	\begin{itemize}
+		\item A new Groundwater Energy (GWE) transport model is introduced to the code base for simulating heat transport in the subsurface.  Additional information for activating the GWE model type within a MODFLOW 6 simulation is available within the mf6io.pdf document.  New example problems have been developed for testing and demonstrating GWE capabilities (in addition to other internal tests that help verify the accuracy of GWE); however, additional changes to the code and input may be necessary in response to user needs and further testing.
 	%	\item xxx
 	%	\item xxx
-	%\end{itemize}
+	\end{itemize}
 
 	%\underline{EXAMPLES}
 	%\begin{itemize}