Improve Issue Boards docs

doc/.vale/gitlab/spelling-exceptions.txt

@@ -76,6 +76,7 @@ Citus
 clonable
 Cloudwatch
 Cobertura
+Codepen
 Cognito
 colocated
 colocating

doc/api/boards.md

@@ -455,7 +455,7 @@ POST /projects/:id/boards/:board_id/lists
 NOTE: **Note:**
 Label, assignee and milestone arguments are mutually exclusive,
 that is, only one of them are accepted in a request.
-Check the [Issue Board docs](../user/project/issue_board.md#summary-of-features-per-tier)
+Check the [Issue Board docs](../user/project/issue_board.md)
 for more information regarding the required license for each list type.
 
 ```shell

doc/user/project/issues/sorting_issue_lists.md

@@ -11,7 +11,7 @@ etc. The available sorting options can change based on the context of the list.
 For sorting by issue priority, see [Label Priority](../labels.md#label-priority).
 
 In group and project issue lists, it is also possible to order issues manually,
-similar to [issue boards](../issue_board.md#issue-ordering-in-a-list).
+similar to [issue boards](../issue_board.md#how-gitlab-orders-issues-in-a-list).
 
 ## Manual sorting
 
@@ -31,6 +31,6 @@ a given list inside your GitLab instance, any time those two issues are subseque
 loaded in any list in the same instance (could be a different project issue list or a
 different group issue list, for example), that ordering will be maintained.
 
-This ordering also affects [issue boards](../issue_board.md#issue-ordering-in-a-list).
+This ordering also affects [issue boards](../issue_board.md#how-gitlab-orders-issues-in-a-list).
 Changing the order in an issue list changes the ordering in an issue board,
 and vice versa.