Fix warnings

Author: gammasoft71

src/xtd.core/include/xtd/time_span.hpp

@@ -26,7 +26,7 @@ namespace xtd {
   /// @par Examples
   /// The following example instantiates a The following example instantiates a xtd::time_span object that represents the difference between two dates. It then displays the xtd::time_span object's properties. object that represents the difference between two dates. It then displays the xtd::time_span object's properties.
   /// @include time_span.cpp
-  class time_span : public xtd::object, xtd::iequatable<time_span>, public icomparable<time_span>, public iformatable {
+  class time_span : public xtd::object, public xtd::iequatable<time_span>, public icomparable<time_span>, public iformatable {
   public:
     /// @name Public Fields
 

src/xtd.drawing/src/xtd/drawing/imaging/frame_dimension.cpp

@@ -7,7 +7,7 @@ using namespace xtd::drawing::imaging;
 frame_dimension::frame_dimension(const xtd::guid& guid) noexcept : guid_(guid) {
 }
 
-const struct guid& frame_dimension::guid() const noexcept {
+const class guid& frame_dimension::guid() const noexcept {
   return guid_;
 }
 

src/xtd.drawing/src/xtd/drawing/imaging/image_format.cpp

@@ -4,10 +4,10 @@ using namespace xtd;
 using namespace xtd::drawing;
 using namespace xtd::drawing::imaging;
 
-image_format::image_format(const struct guid& guid) noexcept : guid_(guid) {
+image_format::image_format(const class guid& guid) noexcept : guid_(guid) {
 }
 
-const struct guid image_format::guid() const noexcept {
+const class guid image_format::guid() const noexcept {
   return guid_;
 }