Feature: Support multiple function examples

[hatamiarash7]

With the current configuration:

1. We can only have one function example for extensions
2. The output will be an array with one element because of direct export to markdown using the -markdown flag and varchar[] type

In this PR, the procedure of function extraction is changed to produce a multiline example of functions in the final cell. Also, show all examples as a <code> block to look better.

Before:

After:

Users can add multiple examples for their functions using a \n delimiter:

function,description,comment,example
"extract_domain","Extracting the main domain from a URL","","SELECT extract_domain('a.example.com') as domain;\nSELECT extract_domain('b.example.com') as domain;"

[carlopi]

Thanks, this makes sense, I would need to test this and come back.

[hatamiarash7]

@carlopi, did you have a chance to test it?

I saw that new changes had been applied, and there was a conflict. This was fixed, and I updated again.