Fixed some issues on guides to standardize with the rest of the project

[galoget]

In this PR I fixed some issues on various guides to standardize with the rest of the project.

The changes include:

• Applying bullets to "Scenario resources", so markdown shows them in a correct way.
• Deleted some trailing spaces that I found during my review.
• Applied the same titles for some sections in the guide.
• Applied same new lines (spacing), so markdown is rendered correctly (Size and Difficulty are together in certain guides).
• Fixed some wrong numbering. In a level the word "secret" was part of the previous paragraph and not an element itself.

I am not done yet with checking all the guides, but this is the current progress I made.