Convert docstring from rst to markdown

[wm-wm-wm]

Change Summary

Converted docstrings from rst to markdown

Related issue number

DOP-37575

Checklist

• Commit message and PR title is comprehensive
• Keep the change as small as possible
• Unit and integration tests for the changes exist
• Tests pass on CI and coverage does not decrease
• Documentation reflects the changes where applicable
• docs/changelog/next_release/<pull request or issue id>.<change type>.rst file added describing change
  (see CONTRIBUTING.rst for details.)
• My PR is ready to review.

[github-actions]

Coverage Report •

File	Stmts	Miss	Branch	BrPart	Cover	Missing
syncmaster/exceptions
auth.py	22	5	0	0	77%	32, 39–40, 44, 48
syncmaster/server/dependencies
stub.py	16	3	6	2	81%	34, 39, 43
syncmaster/server/settings/server
static_files.py	17	9	6	6	47%	33–41
syncmaster/worker/handlers/db
clickhouse.py	65	13	20	12	80%	106, 112–121, 123–124
syncmaster/worker/settings
hwm_store.py	18	3	4	2	83%	64–66
TOTAL	5368	642	832	174	88%