Synced instructions to problem specs for feb. (#4102)

Author: BethanyG

exercises/practice/killer-sudoku-helper/.docs/instructions.md

@@ -81,5 +81,5 @@ The screenshots above have been generated using F-Puzzles.com, a Puzzle Setting
 [one-solution-img]: https://assets.exercism.org/images/exercises/killer-sudoku-helper/example1.png
 [four-solutions-img]: https://assets.exercism.org/images/exercises/killer-sudoku-helper/example2.png
 [not-possible-img]: https://assets.exercism.org/images/exercises/killer-sudoku-helper/example3.png
-[clover-puzzle]: https://app.crackingthecryptic.com/sudoku/HqTBn3Pr6R
+[clover-puzzle]: https://sudokupad.app/HqTBn3Pr6R
 [goodliffe-video]: https://youtu.be/c_NjEbFEeW0?t=1180

exercises/practice/markdown/.docs/instructions.md

@@ -10,4 +10,4 @@ Your challenge is to re-write this code to make it easier to read and maintain w
 It would be helpful if you made notes of what you did in your refactoring in comments so reviewers can see that, but it isn't strictly necessary.
 The most important thing is to make the code better!
 
-[markdown]: https://guides.github.com/features/mastering-markdown/
+[markdown]: https://docs.github.com/en/get-started/writing-on-github/getting-started-with-writing-and-formatting-on-github/basic-writing-and-formatting-syntax

exercises/practice/relative-distance/.docs/instructions.md

@@ -36,4 +36,4 @@ Isla and Tariq are siblings and have a separation of 1.
 Similarly, this implementation would report a separation of 2 from you to your father's brother.
 ~~~~
 
-[six-bacons]: https://en.m.wikipedia.org/wiki/Six_Degrees_of_Kevin_Bacon
+[six-bacons]: https://en.wikipedia.org/wiki/Six_Degrees_of_Kevin_Bacon

exercises/practice/rest-api/.docs/instructions.md

@@ -43,6 +43,6 @@ Your task is to implement a simple [RESTful API][restful-wikipedia] that receive
 
 [restful-wikipedia]: https://en.wikipedia.org/wiki/Representational_state_transfer
 [iou]: https://en.wikipedia.org/wiki/IOU
-[github-rest]: https://developer.github.com/v3/
+[github-rest]: https://docs.github.com/en/rest
 [reddit-rest]: https://web.archive.org/web/20231202231149/https://www.reddit.com/dev/api/
 [restfulapi]: https://restfulapi.net/