fix: birdwatcher template and document issues (#849)

* fix: error message for unimplemented function in the template

* docs: fix the word `immutable`

* docs: enhance the word `data-structure`

* docs: fix the word `immutable` in concepts

* docs: unify the line 7 among 3 different files

Author: MojtabaHs

concepts/for-loops/about.md

@@ -4,12 +4,12 @@ Looping is a fundamental concept in programming that allows you to execute a blo
 In Swift, there are two types of loops: [`for-in` loops][for-loops] and `while` loops. 
 In this chapter, you'll learn about `for-in` loops.
 
-For loops allows you to iterate over a sequence of values, taking each element in turn, and binding it to a variable of your choosing.
+For loops allows you to iterate over a sequence of values, taking each element in turn, binding it to a variable of your choosing.
 Swift allows you to iterate over a variety of sequences, such as ranges, arrays, and strings (and more types which will be covered later).
 When every element of the sequence has been iterated over, the loop exits.
 
 For loops are declared by using the `for` keyword, followed by a variable name, the `in` keyword, and a sequence of values to iterate over.
-The variable given in the `for-in` loop is inmutable, meaning you can't change its value inside the loop.
+The variable given in the `for-in` loop is immutable, meaning you can't change its value inside the loop.
 Here's an example of a `for-in` loop that iterates over an array of numbers:
 
 ```swift

concepts/for-loops/introduction.md

@@ -9,7 +9,7 @@ Swift allows you to iterate over a variety of sequences, such as ranges, arrays,
 When every element of the sequence has been iterated over, the loop exits.
 
 For loops are declared by using the `for` keyword, followed by a variable name, the `in` keyword, and a sequence of values to iterate over.
-The variable given in the `for-in` loop is inmutable, meaning you can't change its value inside the loop.
+The variable given in the `for-in` loop is immutable, meaning you can't change its value inside the loop.
 Here's an example of a `for-in` loop that iterates over an array of numbers:
 
 ```swift

exercises/concept/bird-watcher/.docs/introduction.md

@@ -9,7 +9,7 @@ Swift allows you to iterate over a variety of sequences, such as ranges, arrays,
 When every element of the sequence has been iterated over, the loop exits.
 
 For loops are declared by using the `for` keyword, followed by a variable name, the `in` keyword, and a sequence of values to iterate over.
-The variable given in the `for-in` loop is inmutable, meaning you can't change its value inside the loop.
+The variable given in the `for-in` loop is immutable, meaning you can't change its value inside the loop.
 Here's an example of a `for-in` loop that iterates over an array of numbers:
 
 ```swift
@@ -46,7 +46,7 @@ number + 1
 
 You can also iterate over a range of numbers using a `for-in` loop.
 This allows you to execute a block of code a specific number of times, for example, the range `1...5` will iterate over the numbers 1, 2, 3, 4, and 5, so the loop will execute 5 times.
-Sometimes you might want to iterate over indexes, in a datastructure like an array, then you can use a `0..<array.count` range.
+Sometimes you might want to iterate over indexes, in a data-structure like an array, then you can use a `0..<array.count` range.
 
 ```swift
 let numbers = [3, 10, 7, 11]

exercises/concept/bird-watcher/Sources/BirdWatcher/BirdWatcher.swift

@@ -7,5 +7,5 @@ func birdsInWeek(_ birdsPerDay: [Int], weekNumber: Int) -> Int {
 }
 
 func fixBirdCountLog(_ birdsPerDay: [Int]) -> [Int] {
-  fatalError("Please implement the birdsInWeek(_:) function")
+  fatalError("Please implement the fixBirdCountLog(_:) function")
 }