Put documentation to bfbs if it is not empty (google#7649)

* Fix C/C++ Create<Type>Direct with sorted vectors

If a struct has a key the vector has to be sorted. To sort the vector
you can't use "const".

* Changes due to code review

* Improve code readability

* Add generate of JSON schema to string to lib

* option indent_step is supported

* Remove unused variables

* Fix break in test

* Fix style to be consistent with rest of the code

* [TS] Fix reserved words as arguments (google#6955)

* [TS] Fix generation of reserved words in object api (google#7106)

* [TS] Fix generation of object api

* [TS] Fix MakeCamel -> ConvertCase

* [C#] Fix collision of field name and type name

* [TS] Add test for struct of struct of struct

* Update generated files

* Add missing files

* [TS] Fix query of null/undefined fields in object api

* Put documentation to bfbs if it is not empty

* Fix monster test bfbs reference files

* Fix generated monster test files

Why they are different when generating it with linux and windows executable?

src/idl_parser.cpp

@@ -3803,7 +3803,7 @@ Offset<reflection::Object> StructDef::Serialize(FlatBufferBuilder *builder,
   const auto name__ = builder->CreateString(qualified_name);
   const auto flds__ = builder->CreateVectorOfSortedTables(&field_offsets);
   const auto attr__ = SerializeAttributes(builder, parser);
-  const auto docs__ = parser.opts.binary_schema_comments
+  const auto docs__ = parser.opts.binary_schema_comments && !doc_comment.empty()
                           ? builder->CreateVectorOfStrings(doc_comment)
                           : 0;
   std::string decl_file_in_project = declaration_file ? *declaration_file : "";
@@ -3861,7 +3861,7 @@ Offset<reflection::Field> FieldDef::Serialize(FlatBufferBuilder *builder,
   auto name__ = builder->CreateString(name);
   auto type__ = value.type.Serialize(builder);
   auto attr__ = SerializeAttributes(builder, parser);
-  auto docs__ = parser.opts.binary_schema_comments
+  auto docs__ = parser.opts.binary_schema_comments && !doc_comment.empty()
                     ? builder->CreateVectorOfStrings(doc_comment)
                     : 0;
   double d;
@@ -3914,7 +3914,7 @@ Offset<reflection::RPCCall> RPCCall::Serialize(FlatBufferBuilder *builder,
                                                const Parser &parser) const {
   auto name__ = builder->CreateString(name);
   auto attr__ = SerializeAttributes(builder, parser);
-  auto docs__ = parser.opts.binary_schema_comments
+  auto docs__ = parser.opts.binary_schema_comments && !doc_comment.empty()
                     ? builder->CreateVectorOfStrings(doc_comment)
                     : 0;
   return reflection::CreateRPCCall(
@@ -3942,7 +3942,7 @@ Offset<reflection::Service> ServiceDef::Serialize(FlatBufferBuilder *builder,
   const auto name__ = builder->CreateString(qualified_name);
   const auto call__ = builder->CreateVector(servicecall_offsets);
   const auto attr__ = SerializeAttributes(builder, parser);
-  const auto docs__ = parser.opts.binary_schema_comments
+  const auto docs__ = parser.opts.binary_schema_comments && !doc_comment.empty()
                           ? builder->CreateVectorOfStrings(doc_comment)
                           : 0;
   std::string decl_file_in_project = declaration_file ? *declaration_file : "";
@@ -3980,7 +3980,7 @@ Offset<reflection::Enum> EnumDef::Serialize(FlatBufferBuilder *builder,
   const auto vals__ = builder->CreateVector(enumval_offsets);
   const auto type__ = underlying_type.Serialize(builder);
   const auto attr__ = SerializeAttributes(builder, parser);
-  const auto docs__ = parser.opts.binary_schema_comments
+  const auto docs__ = parser.opts.binary_schema_comments && !doc_comment.empty()
                           ? builder->CreateVectorOfStrings(doc_comment)
                           : 0;
   std::string decl_file_in_project = declaration_file ? *declaration_file : "";
@@ -4025,7 +4025,7 @@ Offset<reflection::EnumVal> EnumVal::Serialize(FlatBufferBuilder *builder,
   const auto name__ = builder->CreateString(name);
   const auto type__ = union_type.Serialize(builder);
   const auto attr__ = SerializeAttributes(builder, parser);
-  const auto docs__ = parser.opts.binary_schema_comments
+  const auto docs__ = parser.opts.binary_schema_comments && !doc_comment.empty()
                           ? builder->CreateVectorOfStrings(doc_comment)
                           : 0;
   return reflection::CreateEnumVal(*builder, name__, value, type__, docs__,