refactor(docs): consolidate MS Office document conversion guides

next_docs/en/user_guide/quick_start.rst

@@ -9,7 +9,4 @@ Want to learn about the usage methods under different scenarios ? This page give
 
     quick_start/convert_pdf 
     quick_start/convert_image
-    quick_start/convert_ppt
-    quick_start/convert_pptx
-    quick_start/convert_doc
-    quick_start/convert_docx
+    quick_start/convert_ms_office