Updated instructions.md in Salary Calculator

exercises/concept/salary-calculator/.docs/instructions.md

@@ -1,6 +1,6 @@
 # Instructions
 
-In this exercise, you'll be implementing rules for calculating the total salary of a employee in a month.
+In this exercise, you'll be implementing rules for calculating the total salary of an employee in a month.
 The International Siderurgy Company (ISC) requires assistance in calculating employee salaries, considering various factors that can impact the final wage.
 
 You have three tasks, and you should use the ternary operator instead of if/else statements to implement them.