crude latex macro for \<newline;

--- a/lib/texinputs/isabellesym.sty	Sat Jan 18 19:35:42 2014 +0100
+++ b/lib/texinputs/isabellesym.sty	Sat Jan 18 19:46:58 2014 +0100
@@ -356,4 +356,5 @@
 \newcommand{\isasymsome}{\isamath{\epsilon\,}}
 \newcommand{\isasymopen}{\isatext{\raise.3ex\hbox{$\scriptscriptstyle\langle$}}}
 \newcommand{\isasymclose}{\isatext{\raise.3ex\hbox{$\scriptscriptstyle\rangle$}}}
+\newcommand{\isasymnewline}{\isatext{\fbox{$\hookleftarrow$}}}