[SourceKit] Report container type USRs in the response to cursor-info request.

Typically, users jump to type-specific interface from a member of that type, for
instance, a.getSomething(). To generate the interface, we need to report the USR
of the container type of "getSomething()", which is the USR for the type of a,
 when cursor info is requested for this function call.

tools/SourceKit/lib/SwiftLang/SwiftLangSupport.cpp

@@ -701,6 +701,10 @@ bool SwiftLangSupport::printDeclTypeUSR(const ValueDecl *D, llvm::raw_ostream &O
   return ide::printDeclTypeUSR(D, OS);
 }
 
+bool SwiftLangSupport::printTypeUSR(Type Ty, llvm::raw_ostream &OS) {
+  return ide::printTypeUSR(Ty, OS);
+}
+
 bool SwiftLangSupport::printAccessorUSR(const AbstractStorageDecl *D,
                                         AccessorKind AccKind,
                                         llvm::raw_ostream &OS) {