Update project_euler/problem_007/sol1.rb

Co-authored-by: Stepfen Shawn <m18824909883@163.com>

Author: domix80

project_euler/problem_007/sol1.rb

@@ -1,6 +1,6 @@
 #Project Euler Problem 7:  https://projecteuler.net/problem=7
 #10001st prime
-#By listing the first six prime numbers: 2, 3, 5, 7, 11, #and 13, we
+#By listing the first six prime numbers: 2, 3, 5, 7, 11, and 13, we
 #can see that the 6th prime is 13.
 #What is the 10001st prime number?
 #References: https://en.wikipedia.org/wiki/Prime_number