docs(api_split.pug): add "code" to parameter name

[hasezoey]

Summary

This changes Documentation Parameter names from "someOption" to someOption, which in my opinion is better to read

before:

after:

before/after with darkreader

before:

after:

[hasezoey]

By the way, should the headers maybe also be wrapped in code-blocks too?

[vkarpov15]

You're right, much easier to read. Thanks!

[vkarpov15]

@hasezoey headers would be a good idea too. As long as that doesn't screw up header ids.