docs: Set the date for the 6.0.0 release

Author: claremacrae

docs/Introduction.md

@@ -17,7 +17,7 @@ _In recent [releases](https://github.com/obsidian-tasks-group/obsidian-tasks/rel
   - Add [[Custom Sorting|custom sorting]].
   - Document the [[Sorting#Default sort order|default sort order]].
   - **Warning**: This release contains some **bug-fixes** to **sorting** and to treatment of **invalid dates**.
-    - The changes are detailed in [[breaking changes#Tasks X.Y.Z (21 January 2024)|breaking changes]], even though they are all improvements to the previous behaviour.
+    - The changes are detailed in [[breaking changes#Tasks X.Y.Z (19 January 2024)|breaking changes]], even though they are all improvements to the previous behaviour.
     - You may need to update any CSS snippets for the Edit or Postpone buttons: see [[How to style buttons]].
 - 5.6.0:
   - The [[Postponing|postpone]] menu now offers `today` and `tomorrow`.

docs/Support and Help/Breaking Changes.md

@@ -41,7 +41,7 @@ To help users updating across multiple Tasks releases, we collect here links to
 
 - The meaning of final backslash (`\`) characters on query lines [[Line Continuations#Appendix Updating pre-5.0.0 searches with trailing backslashes|has changed]].
 
-## Tasks X.Y.Z (21 January 2024)
+## Tasks X.Y.Z (19 January 2024)
 
 *Release notes: [Tasks X.Y.Z](https://github.com/obsidian-tasks-group/obsidian-tasks/releases/tag/X.Y.Z).*