Remove the unnecessary symbols in code examples

Use case: I want to be able to copy and paste code from out documentation into my (sql) console. This isn’t possible right now, as there are leading dots with new lines like so:

Feature description: Only use valid code in examples and move any additional info in valid comment syntax e.g.:

CREATE FUNCTION my_subtract_function(integer, integer)
RETURNS integer
LANGUAGE JAVASCRIPT
AS 'function my_subtract_function(a, b) { return a - b; }';
-- CREATE OK, 1 row affected  (... sec)

[mfussenegger]

We could also try out using testcode and testoutput directives: https://www.sphinx-doc.org/en/master/usage/extensions/doctest.html#directive-testcode

That might allow us to leave out the dots

[proddata]

Since we now integrated the copy-button, I will close this 🙂