Fix style of the first ten solutions for Project Euler (#3242)

* Fix style of the first ten solutions for Project Euler

- Unify the header docstring, and add reference URLs to wikipedia
  or similar
- Fix docstrings to be properly multilined
- Add newlines where appropriate
- Add doctests where they were missing
- Remove doctests that test for the correct solution
- fix obvious spelling or grammar mistakes in comments and
  exception messages
- Fix line endings to be UNIX. This makes two of the files seem
  to have changed completely
- no functional changes in any of the solutions were done
  (except for the spelling fixes mentioned above)

* Fix docstrings and main function as per Style Guide

project_euler/problem_008/sol1.py

@@ -1,33 +1,36 @@
 """
-Problem 8: https://projecteuler.net/problem=8
+Project Euler Problem 8: https://projecteuler.net/problem=8
+
+Largest product in a series
 
 The four adjacent digits in the 1000-digit number that have the greatest
 product are 9 × 9 × 8 × 9 = 5832.
 
-73167176531330624919225119674426574742355349194934
-96983520312774506326239578318016984801869478851843
-85861560789112949495459501737958331952853208805511
-12540698747158523863050715693290963295227443043557
-66896648950445244523161731856403098711121722383113
-62229893423380308135336276614282806444486645238749
-30358907296290491560440772390713810515859307960866
-70172427121883998797908792274921901699720888093776
-65727333001053367881220235421809751254540594752243
-52584907711670556013604839586446706324415722155397
-53697817977846174064955149290862569321978468622482
-83972241375657056057490261407972968652414535100474
-82166370484403199890008895243450658541227588666881
-16427171479924442928230863465674813919123162824586
-17866458359124566529476545682848912883142607690042
-24219022671055626321111109370544217506941658960408
-07198403850962455444362981230987879927244284909188
-84580156166097919133875499200524063689912560717606
-05886116467109405077541002256983155200055935729725
-71636269561882670428252483600823257530420752963450
+    73167176531330624919225119674426574742355349194934
+    96983520312774506326239578318016984801869478851843
+    85861560789112949495459501737958331952853208805511
+    12540698747158523863050715693290963295227443043557
+    66896648950445244523161731856403098711121722383113
+    62229893423380308135336276614282806444486645238749
+    30358907296290491560440772390713810515859307960866
+    70172427121883998797908792274921901699720888093776
+    65727333001053367881220235421809751254540594752243
+    52584907711670556013604839586446706324415722155397
+    53697817977846174064955149290862569321978468622482
+    83972241375657056057490261407972968652414535100474
+    82166370484403199890008895243450658541227588666881
+    16427171479924442928230863465674813919123162824586
+    17866458359124566529476545682848912883142607690042
+    24219022671055626321111109370544217506941658960408
+    07198403850962455444362981230987879927244284909188
+    84580156166097919133875499200524063689912560717606
+    05886116467109405077541002256983155200055935729725
+    71636269561882670428252483600823257530420752963450
 
 Find the thirteen adjacent digits in the 1000-digit number that have the
 greatest product. What is the value of this product?
 """
+
 import sys
 
 N = """73167176531330624919225119674426574742355349194934\
@@ -53,12 +56,18 @@ N = """73167176531330624919225119674426574742355349194934\
 
 
 def solution(n: str = N) -> int:
-    """Find the thirteen adjacent digits in the 1000-digit number n that have
+    """
+    Find the thirteen adjacent digits in the 1000-digit number n that have
     the greatest product and returns it.
 
-    >>> solution(N)
-    23514624000
+    >>> solution("13978431290823798458352374")
+    609638400
+    >>> solution("13978431295823798458352374")
+    2612736000
+    >>> solution("1397843129582379841238352374")
+    209018880
     """
+
     largest_product = -sys.maxsize - 1
     for i in range(len(n) - 12):
         product = 1
@@ -70,4 +79,4 @@ def solution(n: str = N) -> int:
 
 
 if __name__ == "__main__":
-    print(solution(N))
+    print(f"{solution() = }")