Fix style of colored-man-pages plugin

plugins/colored-man-pages/colored-man-pages.plugin.zsh

-if [ "$OSTYPE[0,7]" = "solaris" ]
+if [ "$OSTYPE" = solaris* ]
 then
-	if [ ! -x ${HOME}/bin/nroff ]
+	if [ ! -x "$HOME/bin/nroff" ]
 	then
-		mkdir -p ${HOME}/bin
-		cat > ${HOME}/bin/nroff <<EOF
+		mkdir -p "$HOME/bin"
+		cat > "$HOME/bin/nroff" <<EOF
 #!/bin/sh
 if [ -n "\$_NROFF_U" -a "\$1,\$2,\$3" = "-u0,-Tlp,-man" ]; then
 	shift
-	exec /usr/bin/nroff -u\${_NROFF_U} "\$@"
+	exec /usr/bin/nroff -u\$_NROFF_U "\$@"
 fi
 #-- Some other invocation of nroff
 exec /usr/bin/nroff "\$@"
 EOF
-	chmod +x ${HOME}/bin/nroff
+		chmod +x "$HOME/bin/nroff"
 	fi
 fi