Fix reddit links with internet archive (#2353)

Author: senekor

exercises/rest-api/description.md

@@ -44,5 +44,5 @@ 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/
-[reddit-rest]: https://www.reddit.com/dev/api/
+[reddit-rest]: https://web.archive.org/web/20231202231149/https://www.reddit.com/dev/api/
 [restfulapi]: https://restfulapi.net/

exercises/spiral-matrix/metadata.toml

@@ -1,4 +1,4 @@
 blurb = "Given the size, return a square matrix of numbers in spiral order."
 source = "Reddit r/dailyprogrammer challenge #320 [Easy] Spiral Ascension."
-source_url = "https://www.reddit.com/r/dailyprogrammer/comments/6i60lr/20170619_challenge_320_easy_spiral_ascension/"
+source_url = "https://web.archive.org/web/20230607064729/https://old.reddit.com/r/dailyprogrammer/comments/6i60lr/20170619_challenge_320_easy_spiral_ascension/"
 title = "Spiral Matrix"

exercises/transpose/metadata.toml

@@ -1,4 +1,4 @@
 title = "Transpose"
 blurb = "Take input text and output it transposed."
 source = "Reddit r/dailyprogrammer challenge #270 [Easy]."
-source_url = "https://www.reddit.com/r/dailyprogrammer/comments/4msu2x/challenge_270_easy_transpose_the_input_text"
+source_url = "https://web.archive.org/web/20230630051421/https://old.reddit.com/r/dailyprogrammer/comments/4msu2x/challenge_270_easy_transpose_the_input_text/"