docs(crossword): fix grammar and add details to subject

subjects/crossword/README.md

@@ -2,7 +2,7 @@
 
 ### Instructions
 
-Create the function `crosswordSolver` that is able to solve an empty crossword puzzle.
+Create the function `crosswordSolver` that is able to solve an empty crossword puzzle. The function must be submitted in a file named `crosswordSolver.js`.
 
 The function takes two arguments:
 1. an empty puzzle, passed as a string and
@@ -12,7 +12,7 @@ The function must print on the console a string representing the puzzle filled w
 
 The empty puzzle will be a string with the following rules:
 - each character will be either a number, a `.` or a `\n`;
-- a number represent the number of words starting from the specific position and a `.` represent a space that does not need to be filled. 
+- a number represents the number of words starting from the specific position and a `.` represents a space that does not need to be filled. 
 
 If the puzzle or list of words provided as inputs does not guarantee a unique solution, or any other conditions stated above are not met, the function must print `'Error'`. 
 
@@ -28,7 +28,8 @@ const emptyPuzzle =
 `
 const words = ['casa', 'alan', 'ciao', 'anta']
 
-console.log(crosswordSolver(emptyPuzzle, words))
+crosswordSolver(emptyPuzzle, words)
+
 /* output:
 `
 casa