Add Support For PPTX Shape Groups (Fix in code design to not miss out on slide content) (#331)

* Adds support for Shape Groups

* Update to Test PPtx for nested shape

* This line was accidentally removed and is added back here

packages/markitdown/src/markitdown/converters/_pptx_converter.py

@@ -64,7 +64,9 @@ class PptxConverter(HtmlConverter):
             md_content += f"\n\n<!-- Slide number: {slide_num} -->\n"
 
             title = slide.shapes.title
-            for shape in slide.shapes:
+
+            def get_shape_content(shape, **kwargs):
+                nonlocal md_content
                 # Pictures
                 if self._is_picture(shape):
                     # https://github.com/scanny/python-pptx/pull/512#issuecomment-1713100069
@@ -134,6 +136,14 @@ class PptxConverter(HtmlConverter):
                     else:
                         md_content += shape.text + "\n"
 
+                # Group Shapes
+                if shape.shape_type == pptx.enum.shapes.MSO_SHAPE_TYPE.GROUP:
+                    for subshape in shape.shapes:
+                        get_shape_content(subshape, **kwargs)
+
+            for shape in slide.shapes:
+                get_shape_content(shape, **kwargs)
+
             md_content = md_content.strip()
 
             if slide.has_notes_slide: