Doxygen: Add bullet points to subpages lists & link webpage on welcome page (#6377)

* add bullet points to subpages

* Link to webpage from welcome page

* Add bullet points to subpages

* grouping

* Add TODO note to card database documentation

Added a TODO note for future updates.

* Fix GH alerts commands to be doxygen compatible

doc/doxygen/extra-pages/user_documentation/deck_management/editing_decks.md

@@ -1,7 +1,6 @@
 @page editing_decks Editing Decks
 
-@subpage editing_decks_classic
+ - @subpage editing_decks_classic
+ - @subpage editing_decks_visual
 
-@subpage editing_decks_visual
-
-@subpage editing_decks_printings
+ - @subpage editing_decks_printings

doc/doxygen/extra-pages/user_documentation/index.md

@@ -1,13 +1,9 @@
 @page user_reference User Reference
 
-@subpage search_syntax_help
-
-@subpage deck_search_syntax_help
-
-@subpage creating_decks
-
-@subpage importing_decks
-
-@subpage editing_decks
-
-@subpage exporting_decks
+- @subpage search_syntax_help
+- @subpage deck_search_syntax_help
+ 
+- @subpage creating_decks
+- @subpage importing_decks
+- @subpage editing_decks
+- @subpage exporting_decks