[CONTENT] New adventures to explain new pygame keywords

[daandj]

❗ https://github.com/Felienne/hedy/issues/3337 has to be completed first, otherwise the new adventure won't work.

Issue #3337 adds a new keyword 'pressed' to the hedy language of level 5. In order for the students to learn about this keyword and how to use it, a new adventure should be added to level 5 with an example and explanation.