No spacing between the image and the text when image is aligned left or right and text is flowing around it

How to reproduce:

• Create a new page or edit the standard sandbox
• add an image at the beginning of the page (or anywhere in the page)
• select left alignment from the editor
  • for this issue the expected syntax of the image is [[image:xwiki2.png||alt="xwiki2.png" style="float: left;" width="400px"]]

Expected result:

• the image is displayed aligned on the left and the text of the page is flowing around it, in a visually readable way, with some whitespace separating visually the image from the text floating around it

Actual result:

• the text is stuck to the image, making is unpleasant visually and a bit difficult to read

Note: related issue XWIKI-20637 is also visible in this screenshot.