Fix docstring examples

[brandenchan]

This PR reformats a few code examples in the docstrings so that they render correctly

[PiffPaffM]

It looks good in haystack-website, but we have two ways to format examples:

Let's agree on one approach.

[brandenchan]

@PiffPaffM I went for the vertical bar approach because I find that visually a little cleaner, especially on the website. I also put the vertical bar before the opening dictionary brackets so that we have an aligned starting point for each line.

I think I might even indent everything by one tab so there is some separation between vertical bar and dictionary brackets.

Do you have any thoughts or preferences on this?

[PiffPaffM]

@brandenchan Makes sense to me. I would suggest that we try this out. Let me know when pushed your changes. I will render it on the website and we can have a look.

[brandenchan]

@PiffPaffM Ok cool, in the latest commit I have unified all examples to use | and also added spaces between | and the start of the line

[PiffPaffM]

@brandenchan
Here is an example with spaces:

Here is an example with out spaces:

I would go with the variant with spaces.

[bglearning]

@brandenchan The rendering seems to be incorrect now (not sure why exactly, probably due to the vertical bars?)

E.g on the BM25Retriever reference.

Maybe we can create a new issue