fix(curriculum): clean-up Project Euler 301-320 (#42926)

* fix: clean-up Project Euler 301-320

* fix: corrections from review

Co-authored-by: Tom <20648924+moT01@users.noreply.github.com>

Co-authored-by: Tom <20648924+moT01@users.noreply.github.com>

curriculum/challenges/english/10-coding-interview-prep/project-euler/problem-301-nim.md

@@ -12,25 +12,30 @@ Nim is a game played with heaps of stones, where two players take it in turn to
 
 We'll consider the three-heap normal-play version of Nim, which works as follows:
 
--   At the start of the game there are three heaps of stones.
--   On his turn the player removes any positive number of stones from any single heap.
--   The first player unable to move (because no stones remain) loses.
+- At the start of the game there are three heaps of stones.
+- On his turn the player removes any positive number of stones from any single heap.
+- The first player unable to move (because no stones remain) loses.
 
-If (n1,n2,n3) indicates a Nim position consisting of heaps of size n1, n2 and n3 then there is a simple function X(n1,n2,n3) — that you may look up or attempt to deduce for yourself — that returns: zero if, with perfect strategy, the player about to move will eventually lose; or non-zero if, with perfect strategy, the player about to move will eventually win. For example X(1,2,3) = 0 because, no matter what the current player does, his opponent can respond with a move that leaves two heaps of equal size, at which point every move by the current player can be mirrored by his opponent until no stones remain; so the current player loses. To illustrate:
+If ($n_1$, $n_2$, $n_3$) indicates a Nim position consisting of heaps of size $n_1$, $n_2$ and $n_3$ then there is a simple function $X(n_1,n_2,n_3)$ — that you may look up or attempt to deduce for yourself — that returns:
 
--   current player moves to (1,2,1)
--   opponent moves to (1,0,1)
--   current player moves to (0,0,1)
--   opponent moves to (0,0,0), and so wins.
+- zero if, with perfect strategy, the player about to move will eventually lose; or
+- non-zero if, with perfect strategy, the player about to move will eventually win.
 
-For how many positive integers n ≤ 230 does X(n,2n,3n) = 0 ?
+For example $X(1, 2, 3) = 0$ because, no matter what the current player does, his opponent can respond with a move that leaves two heaps of equal size, at which point every move by the current player can be mirrored by his opponent until no stones remain; so the current player loses. To illustrate:
+
+- current player moves to (1,2,1)
+- opponent moves to (1,0,1)
+- current player moves to (0,0,1)
+- opponent moves to (0,0,0), and so wins.
+
+For how many positive integers $n ≤ 2^{30}$ does $X(n, 2n, 3n) = 0$?
 
 # --hints--
 
-`euler301()` should return 2178309.
+`nim()` should return `2178309`.
 
 ```js
-assert.strictEqual(euler301(), 2178309);
+assert.strictEqual(nim(), 2178309);
 ```
 
 # --seed--
@@ -38,12 +43,12 @@ assert.strictEqual(euler301(), 2178309);
 ## --seed-contents--
 
 ```js
-function euler301() {
+function nim() {
 
   return true;
 }
 
-euler301();
+nim();
 ```
 
 # --solutions--