Revert "Adds GenericDocument::ParseStream() overload to make SourceEncoding optional"
Revert "Adds GenericDocument::ParseStream() overload to make SourceEncoding optional"

This reverts commit 84f64ba58a73a0898ad78ea239323942b63c6d51.

zhengxle/rapidjson,zhengxle/rapidjson,zhengxle/rapidjson