update iris.sty

docs/iris.sty

@@ -145,7 +145,7 @@
 \newcommand{\mcar}[1]{|#1|}
 \newcommand{\mcarp}[1]{\mcar{#1}^{+}}
 \newcommand{\munit}{\varepsilon}
-\newcommand{\mcore}[1]{\lfloor#1\rfloor}
+\newcommand{\mcore}[1]{\llparenthesis#1\rrparenthesis}
 \newcommand{\mtimes}{\mathbin{\cdot}}
 
 \newcommand{\mupd}{\rightsquigarrow}