Replaced leftover uses of .format with f-strings in the task description text.

UNL SOFT Introduction to Python/Classes/Constructors/task.html

@@ -5,7 +5,7 @@
 <blockquote>
     <code>class Book(object):</code><br>
     <code>&nbsp;&nbsp;&nbsp;&nbsp;def __init__(self, comment):</code><br>
-    <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;print('Created a book with the comment {comment}'.format(comment=comment))</code>
+    <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;print(f'Created a book with the comment {comment}')</code>
 </blockquote>
 <p>prints a line whenever a book object is created.  The call to the constructor would look like this:</p>
 <blockquote><code>a_book = Book('(400 pages)')</code></blockquote>

UNL SOFT Introduction to Python/Loops/Break and Else/task.html

@@ -5,10 +5,10 @@
     it, but need additional code in case they never find what they are looking for.  For example:</p>
 <blockquote><code>for i in range(10):</code><br>
     <code>&nbsp;&nbsp;&nbsp;&nbsp;if i ** 3 == 500:</code><br>
-    <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;print('The cube root of 500 is {i}.'.format(i=i))</code><br>
+    <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;print(f'The cube root of 500 is {i}.')</code><br>
     <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;break</code><br>
     <code>else:</code><br>
-    <code>&nbsp;&nbsp;&nbsp;&nbsp;print('The cube root of 500 is not an integer between 0 and 9.'.format(i=i))</code>
+    <code>&nbsp;&nbsp;&nbsp;&nbsp;print('The cube root of 500 is not an integer between 0 and 9.')</code>
 </blockquote>
 <p>Fill in the placeholders so that the actual outputs match the expected outputs.</p>
 </html>