Some day we will have ANSI C compatibility... This change doesn't make the API backwards incompatible because uint32_t was only used in flags to json_dump*() and the flags are meant to be used only by ORing constants and macro output, and actually currently only JSON_INDENT can be used.
To build the documentation, invoke
sphinx-build . .build/html
in this directory. Then point your browser to .build/html/index.html.