Continue documentation cleanup

Reformat some more public/ header documentation.

Review URL: https://codereview.chromium.org/1917103002
diff --git a/public/fpdf_ppo.h b/public/fpdf_ppo.h
index e7d7767..532494e 100644
--- a/public/fpdf_ppo.h
+++ b/public/fpdf_ppo.h
@@ -13,35 +13,31 @@
 extern "C" {
 #endif
 
-// Function: FPDF_ImportPages
-//          Import some pages to a PDF document.
-// Parameters:
-//          dest_doc    -   The destination document which add the pages.
-//          src_doc     -   A document to be imported.
-//          pagerange   -   A page range string, Such as "1,3,5-7".
-//                          If this parameter is NULL, it would import all pages
-//                          in src_doc.
-//          index       -   The page index wanted to insert from.
-// Return value:
-//          TRUE for succeed, FALSE for Failed.
+// Import pages to a FPDF_DOCUMENT.
+//
+//   dest_doc  - The destination document for the pages.
+//   src_doc   - The document to be imported.
+//   pagerange - A page range string, Such as "1,3,5-7". If |pagerange| is NULL,
+//               all pages from |src_doc| are imported.
+//   index     - The page index to insert at.
+//
+// Returns TRUE on success.
 DLLEXPORT FPDF_BOOL STDCALL FPDF_ImportPages(FPDF_DOCUMENT dest_doc,
                                              FPDF_DOCUMENT src_doc,
                                              FPDF_BYTESTRING pagerange,
                                              int index);
 
-// Function: FPDF_CopyViewerPreferences
-//          Copy the viewer preferences from one PDF document to another.#endif
-// Parameters:
-//          dest_doc    -   Handle to document to write the viewer preferences
-//          to.
-//          src_doc     -   Handle to document with the viewer preferences.
-// Return value:
-//          TRUE for success, FALSE for failure.
+// Copy the viewer preferences from |src_doc| into |dest_doc|.
+//
+//   dest_doc - Document to write the viewer preferences into.
+//   src_doc  - Document to read the viewer preferences from.
+//
+// Returns TRUE on success.
 DLLEXPORT FPDF_BOOL STDCALL FPDF_CopyViewerPreferences(FPDF_DOCUMENT dest_doc,
                                                        FPDF_DOCUMENT src_doc);
 
 #ifdef __cplusplus
-}
-#endif
+}  // extern "C"
+#endif  // __cplusplus
 
 #endif  // PUBLIC_FPDF_PPO_H_