Update exercises/square-root/instructions.md

Co-authored-by: Isaac Good <[email protected]>

Author: xanni

exercises/square-root/instructions.md

@@ -1,6 +1,6 @@
 # Instructions
 
-Your task is to implement a calculation of the square root of a given number.
+Your task is to calculate the square root of a given number.
 
 - Try to avoid using the pre-existing math libraries of your language.
 - As input you’ll be given a positive whole number, i.e. 1, 2, 3, 4…