Contract functions/events in contract API docs should be clearly divided

[szemate]

In the contract API reference documentation layout:

the padding between the name of a contract function/event and the content (blue arrow) is the same size (or bigger) than the padding between the content and the title of the next function/event (red arrow). As a result is it difficult to distinguish between contract functions/events when browsing API docs. The layout should be adjusted so that the distinction is clearer.

@dweng0

[dweng0]

I've created a PR that adjusts the margins so that the content is correctly grouped together