[v3] fix dg-warning examples in docs

[Jonathan Wakely]

        * doc/xml/manual/test.xml: Fix dg-warning examples.

Committed to trunk

Index: doc/xml/manual/test.xml
===================================================================
--- doc/xml/manual/test.xml	(revision 181010)
+++ doc/xml/manual/test.xml	(working copy)
@@ -609,10 +609,10 @@
 // { dg-do compile }
 
 Example 2: Testing for expected warnings on line 36, which all targets fail
-// { dg-warning "string literals" "" { xfail *-*-* } 36
+// { dg-warning "string literals" "" { xfail *-*-* } 36 }
 
 Example 3: Testing for expected warnings on line 36
-// { dg-warning "string literals" "" { target *-*-* } 36
+// { dg-warning "string literals" "" { target *-*-* } 36 }
 
 Example 4: Testing for compilation errors on line 41
 // { dg-do compile }