bugfix(graphql): Fix single line and empty description formatting (#12608)

Co-authored-by: Harry Hopkinson <63599884+Harry-Hopkinson@users.noreply.github.com>
Co-authored-by: fisker Cheung <lionkay@gmail.com>

tests/format/graphql/string/string.graphql

@@ -50,3 +50,11 @@ one: string
 {
   foo(input: {multiline: "ab\ncd"}) { id }
 }
+
+{
+  foo(input: {multiline: """    foo    """}) { id }
+}
+
+{
+  foo(input: {multiline: """    """}) { id }
+}