Documentation embedded in the hover popup is broken in some cases

[lesquoyb]

Describe the bug
I noticed that the documentation of the image layer in the popup window that appears on hovering the image keyword seems broken:
It includes the titles of the usage parts of the documentation without the actual examples, which is really weird:

To Reproduce
Steps to reproduce the behavior:

1. write an image layer in a display
2. hover over the image keyword with your mouse
3. See error

Expected behavior
Either the Usage part is completely ignored, or it is displayed including the examples.
Another alternative would be to write the documentation a bit differently so it won't feel weird to only have the value of usage and not the examples, but I think in that case there's probably a lot of statements and operators to redo.

[AlexisDrogoul]

Should be fixed by 45808cb . Please test.