ToC with duplicated entries

[arnaucasau]

There are pages with duplicated headers that create duplicated entries in the ToC. An example can be found in this page:

In that case, we have functions at the beginning of the page, and afterward, an inlined class that contains two methods with the same name.

[Eric-Arellano]

Fixed by @arnaucasau's header hierarchy improvement 🚀 toc of https://docs.quantum.ibm.com/api/qiskit/0.44/qasm3#dump

There still is a top-level dump function vs Exporter.dump, but now the header is lower for the method so it's not confusing