Correct blurb for the pythagorean-triplet exercise (#2500)

Author: tasxatzial

exercises/pythagorean-triplet/metadata.toml

@@ -1,4 +1,4 @@
 title = "Pythagorean Triplet"
-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"