Fix newlines before the update suffix operator in babel-generator (#6259)

packages/babel-generator/src/generators/expressions.js

@@ -33,7 +33,9 @@ export function UpdateExpression(node: Object) {
     this.token(node.operator);
     this.print(node.argument, node);
   } else {
+    this.startTerminatorless(true);
     this.print(node.argument, node);
+    this.endTerminatorless();
     this.token(node.operator);
   }
 }

packages/babel-generator/test/fixtures/types/UpdateExpression/actual.js

@@ -1,3 +1,4 @@
 ++i;
 i++;
 (foo++).test();
+obj.foo/*comment*/++;

packages/babel-generator/test/fixtures/types/UpdateExpression/expected.js

@@ -1,3 +1,4 @@
 ++i;
 i++;
-(foo++).test();
+(foo++).test();
+obj.foo /*comment*/++;