Fixes for alternative text

[maelle]

In alternative text, when describing an interface

• Do not rely on the left/right position of a thing only. Also add "sidebar", "menu" or similar.
• Add what type of control to expect: drop down, check box, radio button, etc.

We should check this on the posts that are translated to start with (assuming we translated the "most important" posts). Cc @yabellini

[maelle]

I'm going through https://ropensci.org/es/archive/ but I think I might find more things to fix in the R-universe docs, where we do describe interfaces.