Drop svg badges. Even though they were only appearing in the html version, the latexpdf target was still trying to download them, leading to warnings-as-errors in offline builds.
I was thinking about compiling the dummy example and including a simple example usage, but it turns out functional.h isn't (currently) available for extensions.
Acknowledge the minimal functional backend, highlighting what's new/different for our SExpr targets.
Add and use the reference `minimal backend`.
Use `note` directives to point out missing code sections (highlighting that the included diffs are not complete).
Racket *is* still strongly-typed, it's just dynamic instead of static. Adjust phrasing to reflect that.
Adjust some of the literal includes, adding a new section from the `Functional::AbstractVisitor`, splitting the `Module::write_eval()` in twain and adding a `smtlib.cc` literal include for the node iteration, as well as for the `FunctionalSmtBackend` to compare against the minimal backend.
Move `Backend` description up to minimal functional backend section.
Add `dummy.cc`, loosely based on `backends/functional/test_generic.cc` but as an actualy backend and without the memory testing.
Skeleton section for minimal functional backend, describing the aforementioned `dummy.cc`.
As the intro paragraph (now) says:
> This section will introduce the SMT-LIB functional backend and what changes are needed...
The example is intended to be read without prior knowledge of the SMT-LIB backend, but the previous version glossed over a lot and instead focused on *just* what was changed.
This version should now be easier to follow without prior knowledge, while still being able to learn enough about the `Smt` version to adapt it to a different s-expression target that isn't Rosette.
Also adds a few `literalinclude`s of smtlib.cc, which is now copied to `docs/source/generated` along with producing the rosette diff on the fly (which now also has up to 20 lines of context, enabling the full `Module::write()` diff to be literal included).
