Synced practice exercise docs to problem specificatons. (#3573)

exercises/practice/perfect-numbers/.docs/instructions.md

@@ -2,22 +2,38 @@
 
 Determine if a number is perfect, abundant, or deficient based on Nicomachus' (60 - 120 CE) classification scheme for positive integers.
 
-The Greek mathematician [Nicomachus][nicomachus] devised a classification scheme for positive integers, identifying each as belonging uniquely to the categories of **perfect**, **abundant**, or **deficient** based on their [aliquot sum][aliquot-sum].
-The aliquot sum is defined as the sum of the factors of a number not including the number itself.
+The Greek mathematician [Nicomachus][nicomachus] devised a classification scheme for positive integers, identifying each as belonging uniquely to the categories of [perfect](#perfect), [abundant](#abundant), or [deficient](#deficient) based on their [aliquot sum][aliquot-sum].
+The _aliquot sum_ is defined as the sum of the factors of a number not including the number itself.
 For example, the aliquot sum of `15` is `1 + 3 + 5 = 9`.
 
-- **Perfect**: aliquot sum = number
-  - 6 is a perfect number because (1 + 2 + 3) = 6
-  - 28 is a perfect number because (1 + 2 + 4 + 7 + 14) = 28
-- **Abundant**: aliquot sum > number
-  - 12 is an abundant number because (1 + 2 + 3 + 4 + 6) = 16
-  - 24 is an abundant number because (1 + 2 + 3 + 4 + 6 + 8 + 12) = 36
-- **Deficient**: aliquot sum < number
-  - 8 is a deficient number because (1 + 2 + 4) = 7
-  - Prime numbers are deficient
+## Perfect
 
-Implement a way to determine whether a given number is **perfect**.
-Depending on your language track, you may also need to implement a way to determine whether a given number is **abundant** or **deficient**.
+A number is perfect when it equals its aliquot sum.
+For example:
+
+- `6` is a perfect number because `1 + 2 + 3 = 6`
+- `28` is a perfect number because `1 + 2 + 4 + 7 + 14 = 28`
+
+## Abundant
+
+A number is abundant when it is less than its aliquot sum.
+For example:
+
+- `12` is an abundant number because `1 + 2 + 3 + 4 + 6 = 16`
+- `24` is an abundant number because `1 + 2 + 3 + 4 + 6 + 8 + 12 = 36`
+
+## Deficient
+
+A number is deficient when it is greater than its aliquot sum.
+For example:
+
+- `8` is a deficient number because `1 + 2 + 4 = 7`
+- Prime numbers are deficient
+
+## Task
+
+Implement a way to determine whether a given number is [perfect](#perfect).
+Depending on your language track, you may also need to implement a way to determine whether a given number is [abundant](#abundant) or [deficient](#deficient).
 
 [nicomachus]: https://en.wikipedia.org/wiki/Nicomachus
 [aliquot-sum]: https://en.wikipedia.org/wiki/Aliquot_sum

exercises/practice/phone-number/.docs/instructions.md

@@ -11,12 +11,14 @@ The first three digits of the local number represent the _exchange code_, follow
 The format is usually represented as
 
 ```text
-(NXX)-NXX-XXXX
+NXX NXX-XXXX
 ```
 
 where `N` is any digit from 2 through 9 and `X` is any digit from 0 through 9.
 
-Your task is to clean up differently formatted telephone numbers by removing punctuation and the country code (1) if present.
+Sometimes they also have the country code (represented as `1` or `+1`) prefixed.
+
+Your task is to clean up differently formatted telephone numbers by removing punctuation and the country code if present.
 
 For example, the inputs
 

exercises/practice/queen-attack/.docs/instructions.md

@@ -8,18 +8,14 @@ A chessboard can be represented by an 8 by 8 array.
 
 So if you are told the white queen is at `c5` (zero-indexed at column 2, row 3) and the black queen at `f2` (zero-indexed at column 5, row 6), then you know that the set-up is like so:
 
-```text
-  a b c d e f g h
-8 _ _ _ _ _ _ _ _ 8
-7 _ _ _ _ _ _ _ _ 7
-6 _ _ _ _ _ _ _ _ 6
-5 _ _ W _ _ _ _ _ 5
-4 _ _ _ _ _ _ _ _ 4
-3 _ _ _ _ _ _ _ _ 3
-2 _ _ _ _ _ B _ _ 2
-1 _ _ _ _ _ _ _ _ 1
-  a b c d e f g h
-```
+![A chess board with two queens. Arrows emanating from the queen at c5 indicate possible directions of capture along file, rank and diagonal.](https://assets.exercism.org/images/exercises/queen-attack/queen-capture.svg)
 
 You are also able to answer whether the queens can attack each other.
 In this case, that answer would be yes, they can, because both pieces share a diagonal.
+
+## Credit
+
+The chessboard image was made by [habere-et-dispertire][habere-et-dispertire] using LaTeX and the [chessboard package][chessboard-package] by Ulrike Fischer.
+
+[habere-et-dispertire]: https://exercism.org/profiles/habere-et-dispertire
+[chessboard-package]: https://github.com/u-fischer/chessboard

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