isabellebody: \par at begin/end;

--- a/lib/texinputs/isabelle.sty	Tue Nov 14 17:03:13 2000 +0100
+++ b/lib/texinputs/isabelle.sty	Wed Nov 15 00:39:44 2000 +0100
@@ -29,9 +29,10 @@
 \newdimen\isa@parindent\newdimen\isa@parskip
 
 \newenvironment{isabellebody}{%
+\par%
 \isa@parindent\parindent\parindent0pt%
 \isa@parskip\parskip\parskip0pt%
-\isastyle}{}
+\isastyle}{\par}
 
 \newenvironment{isabelle}
 {\begin{trivlist}\begin{isabellebody}\item\relax}