Merge pull request #9 from jetbrains-academy/stephen-hero-patch-5

Update task.md

courseSection/courseLesson/theoryTask/task.md

@@ -1,14 +1,14 @@
-It is an example of a theory lesson.
+This is an example of a theory lesson.
 
 <div class="hint" title="What is the difference between visible and invisible files?">
 
 You can use hints to explain something to the students. 
-Please, leave an empty line to be able to apply Markdown formatting like **this**.
+Please leave an empty line to be able to apply markdown formatting, like **this**.
 
 Invisible files are hidden in the student mode. 
-You can use them to define the helper functions etc in the course.
+You can use them to define, for example, the helper functions in the course.
 
-To mark a file as an invisible file you need to set up the `false` value for the corresponding file in the [task-info](./task-info.yaml) file.
+To mark a file as invisible, you need to set up the `false` value for the corresponding file in the [task-info](./task-info.yaml) file.
 </div>
 
 Theory tasks do not contain any tests.