Fix contributing guide for building the docs

[andreyvelich]

I fixed guide for building the docs:

1. conda env has been changed to jupyter_server_docs
2. We have to use jupyter_server in our doc requirements.
3. I regenerated docs using make html.

cc @Zsailer

[blink1073]

I think the full_config.rst file needs to be added to gitignore, since it is generated on demand.

[andreyvelich]

I think the full_config.rst file needs to be added to gitignore, since it is generated on demand.

That makes sense @blink1073.
We are generating this config as part of conf.py.

[codecov-commenter]

Codecov Report

Merging #794 (0e91104) into main (6740cb5) will decrease coverage by 0.09%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #794      +/-   ##
==========================================
- Coverage   69.99%   69.89%   -0.10%     
==========================================
  Files          62       62              
  Lines        7368     7368              
  Branches     1223     1223              
==========================================
- Hits         5157     5150       -7     
- Misses       1839     1845       +6     
- Partials      372      373       +1     

Impacted Files	Coverage Δ
jupyter_server/services/kernels/handlers.py	57.44% <0.00%> (-1.07%)	⬇️
jupyter_server/services/kernels/kernelmanager.py	79.66% <0.00%> (-0.67%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 6740cb5...0e91104. Read the comment docs.

[blink1073]

Thanks!