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

This reverts commit 84f64ba5.

include/rapidjson/document.h

@@ -788,11 +788,6 @@ public:
 		return *this;
 	}
 
-	template <unsigned parseFlags, typename InputStream>
-	GenericDocument& ParseStream(InputStream& is) {
-		return ParseStream<parseFlags, Encoding, InputStream>(is);
-	}
-
 	//! Parse JSON text from a mutable string.
 	/*! \tparam parseFlags Combination of ParseFlag.
 		\param str Mutable zero-terminated string to be parsed.