liblink: include missing pragmas for plan9 formatter

R=rsc, r, 0intro
CC=golang-codereviews
https://golang.org/cl/36060047

include/plan9/link.h

@@ -3,3 +3,15 @@
 // license that can be found in the LICENSE file.
 
 #include "../link.h"
+
+#pragma	varargck	type	"@"	Addr*
+#pragma	varargck	type	"A"	int
+#pragma	varargck	type	"$"	char*
+#pragma	varargck	type	"D"	Addr*
+#pragma	varargck	type	"lD"	Addr*
+#pragma	varargck	type	"L"	int
+#pragma	varargck	type	"lS"	LSym*
+#pragma	varargck	type	"M"	Addr*
+#pragma	varargck	type	"P"	Prog*
+#pragma	varargck	type	"R"	int
+#pragma	varargck	type	"S"	char*

src/liblink/list5.c

@@ -43,7 +43,7 @@ static int	Aconv(Fmt *fp);
 static int	Dconv(Fmt *fp);
 static int	Mconv(Fmt *fp);
 static int	Pconv(Fmt *fp);
-static int	Rconv(Fmt *fp);
+static int	RAconv(Fmt *fp);
 static int	DSconv(Fmt *fp);
 
 void
@@ -54,7 +54,7 @@ listinit5(void)
 	fmtinstall('$', DSconv);
 	fmtinstall('M', Mconv);
 	fmtinstall('D', Dconv);
-	fmtinstall('R', Rconv);
+	fmtinstall('@', RAconv);
 }
 
 static char *extra [] = {
@@ -85,10 +85,10 @@ Pconv(Fmt *fp)
 		strcat(sc, ".U");
 	if(a == AMOVM) {
 		if(p->from.type == D_CONST)
-			sprint(str, "	%A%s	%R,%D", a, sc, &p->from, &p->to);
+			sprint(str, "	%A%s	%@,%D", a, sc, &p->from, &p->to);
 		else
 		if(p->to.type == D_CONST)
-			sprint(str, "	%A%s	%D,%R", a, sc, &p->from, &p->to);
+			sprint(str, "	%A%s	%D,%@", a, sc, &p->from, &p->to);
 		else
 			sprint(str, "	%A%s	%D,%D", a, sc, &p->from, &p->to);
 	} else
@@ -210,7 +210,7 @@ Dconv(Fmt *fp)
 }
 
 static int
-Rconv(Fmt *fp)
+RAconv(Fmt *fp)
 {
 	char str[STRINGSZ];
 	Addr *a;