Improve the functionDef renderer for long names

[tristanlatr]

Functions with very long parameters names are not rendered in an optimal way.

We should probably add <wbr> tags like we do in annotations.

We could even go further and borrow the _PrettySignature objects from mitmproxy/pdoc repo, such that the longer signatures parameters are padded with 4 spaces: https://github.com/mitmproxy/pdoc/blob/ac29a26b9878a0237f7563c14d193304743b544a/pdoc/doc.py#L942-L1006

[tristanlatr]

Now that I think about it, I don’t think we should pad the signature with 4 spaces when it’s long. Everything should simply be displayed inline, like in Sphinx. the parameter table already take enough space. But we should use the insert break point function.