Document "Edit on" links for multiple projects

[benjaoming]

It's currently complicated to use different repositories for each project and have "Edit on" render correct links. This means being able to add a customizable base URL for each project's repository.

[stsewd]

We have this workaround at our docs

https://github.com/readthedocs/readthedocs.org/blob/b2c809b7ed2235c688621abdb396e3cbec697885/docs/conf.py#L152-L157

[karlsigidex]

@stsewd yes I found that workaround, I think the point of this ticket though is to:

1. Document the fact that "Edit on" links can become broken when using sphinx-multiproject
2. Document the workaround
3. Document that for the workaround to actually work the user has to request that the RTD admins set the DONT_OVERWRITE_SPHINX_CONTEXT flag foreach project

[benjaoming]

The workaround sets conf_py_path such that the path of https://github.com/organization/repo/docs/<docset> is set - but @karlsigidex isn't your use case that you have documentation in several different repositories? Or do you combine all your docs in one repo?

[karlsigidex]

@benjaoming we have multiple documents per repository.

In order to better control our documentation builds (e.g. os,python version, packages, etc.) we need to use a .readthedocs.yaml configuration file.

Currently, having a single configuration file at the root of the repository is incompatible with multiple documents per repository. The workaround is to use sphinx-multiproject.

[benjaoming]

Gotcha, sounds like the current workaround is applicable 👍