Synced metadata for practice exercises. (#3841)

Author: BethanyG

exercises/practice/atbash-cipher/.meta/config.json

@@ -27,7 +27,7 @@
       ".meta/example.py"
     ]
   },
-  "blurb": "Create an implementation of the atbash cipher, an ancient encryption system created in the Middle East.",
+  "blurb": "Create an implementation of the Atbash cipher, an ancient encryption system created in the Middle East.",
   "source": "Wikipedia",
   "source_url": "https://en.wikipedia.org/wiki/Atbash"
 }

exercises/practice/collatz-conjecture/.meta/config.json

@@ -26,6 +26,6 @@
     ]
   },
   "blurb": "Calculate the number of steps to reach 1 using the Collatz conjecture.",
-  "source": "An unsolved problem in mathematics named after mathematician Lothar Collatz",
-  "source_url": "https://en.wikipedia.org/wiki/3x_%2B_1_problem"
+  "source": "Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/Collatz_conjecture"
 }

exercises/practice/pythagorean-triplet/.meta/config.json

@@ -31,7 +31,7 @@
       ".meta/example.py"
     ]
   },
-  "blurb": "There exists exactly one Pythagorean triplet for which a + b + c = 1000. Find the triplet.",
-  "source": "Problem 9 at Project Euler",
+  "blurb": "Given an integer N, find all Pythagorean triplets for which a + b + c = N.",
+  "source": "A variation of Problem 9 from Project Euler",
   "source_url": "https://projecteuler.net/problem=9"
 }