API documentation links seem broken

[Gallaecio]

It seems the use of the Sphinx module and currentmodule directives is corrupting the work made at #5099. If .. module:: scrapy.http is followed by .. class:: scrapy.http.request.form.FormRequest, link-wise the signature of that class is actually scrapy.http.scrapy.http.request.form.FormRequest.

I am hoping there is a simple way to fix this, but I suspect no. I suspect the only way forward is to remove the module directives, requiring us to use absolute paths for every API reference.