Warnings generated while generating HTML in docs folder

### Environment
drf-user developer environment

### Description of the bug

When running ```make html``` in docs folder some warnings are generated.

### What you expected to happen

No warnings

### How to reproduce (as minimally and precisely as possible)

- Setup dev environment
- cd docs
- make html

**WARNINGS:**
```
❯ make html
sphinx-build -b html . _build/html
Running Sphinx v4.2.0
making output directory... done
building [mo]: targets for 0 po files that are out of date
building [html]: targets for 3 source files that are out of date
updating environment: [new config] 3 added, 0 changed, 0 removed
reading sources... [100%] installation al_settings.py
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:24: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:24: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:24: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:24: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:24: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:49: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:49: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:96: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:96: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:96: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:96: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:96: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:119: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:119: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:119: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:119: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:119: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:151: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:151: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:151: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:151: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:178: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:178: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:178: WARNING: Problem in http domain: field
is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:178: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:207: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:207: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:207: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:231: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:231: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:252: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:259: WARNING: Title underline too short.

**Refresh Token**
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:259: WARNING: Title underline too short.

**Refresh Token**
/home/aayush/Projects/prs/drf-user/docs/api-doc.rst:274: WARNING: Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.

looking for now-outdated files... none found
pickling environment... done
checking consistency... done
preparing documents... done
writing output... [100%] installation
generating indices... genindex http-routingtable done
writing additional pages... search done
copying static files... done
copying extra files... done
dumping search index in English (code: en)... done
dumping object inventory... done
build succeeded, 34 warnings.

The HTML pages are in _build/html.

Build finished. The HTML pages are in _build/html
```

The warnings are from Sphinx when building docs in the docs folder. Look at api-doc.rst lines 24, 49, 96, 119, 151, 178, 207, 231, 252, 259, 274. The 'http domain' warnings suggest a role 'obj' is missing; check Sphinx's http extension configuration. The title underline warning at line 259 means the underline length doesn't match the title. Run 'make html' in docs to see warnings, then edit api-doc.rst to fix the formatting and domain references. Done when 'make html' runs with zero warnings.

索引モデルが issue の本文から書いたものです。