CI: markdown link checker (#7145)

* change (CI): markdown link checker

* Fix some invalid doc links (re-run of cargo-unleash gen-readme w/ fixes).

* Fix some invalid doc links

* Fix some invalid doc links

* Fix some links

* Fix some links

* Apply @bkchr suggestions from code review

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Fix more links

* Fix more links

* typo

* Fix more links

* Fix more links

* Ignore valid link .. check wrongly sees it as invalid

* Fix style issue

* Fix style issue

* change (CI): update style guide link

* change (lib): suggestions

Co-authored-by: Dan Forbes <dan@danforbes.dev>
Co-authored-by: Steve Degosserie <steve@parity.io>
Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

substrate/frame/society/README.md

@@ -24,7 +24,7 @@ Of the non-suspended members, there is always a:
 
 Of the non-suspended members of the society, a random set of them are chosen as
 "skeptics". The mechanics of skeptics is explained in the
-[member phase](#member-phase) below.
+[member phase](https://docs.rs/pallet-society/latest/pallet_society/#member-phase) below.
 
 ### Mechanics