[docs] Update pages referencing macros

[critesjosh]

Review existing pages

Aztec macros have changed as part of this PR

We need to do a pass of the docs and make sure that all of the references to macros follow the new convention. For example, this page is out of date.

Add blurb on Public calls

Also, an update to how public functions actually work (related to macros, source):

Contracts that include public functions (that is, marked with #[public]), are required to have a function public_dispatch(selector: Field) which acts as an entry point. This will be soon the only public function registered/deployed in contracts. The calling convention is updated so that external calls are made to this function.

If you are writing your contracts using Aztec-nr, there is nothing you need to change. The public_dispatch function is automatically generated by the #[aztec] macro.