docs: improve docstrings #18041

Job	Run time
cargo deny	35s
Lint Rust	2m 30s
Check if node constants are up to date	8s
Rust doc comments	18s
Check provider database	6s
Rust tests (ubuntu-latest, 1.84.0)	3m 6s
Rust tests (windows-latest, 1.84.0)	9m 19s
Rust tests (macos-latest, 1.84.0)	4m 13s
Rust tests (ubuntu-latest, 1.81.0)	2m 57s
Build C library (ubuntu-latest)	2m 36s
Python lint	11s
Build C library (macos-latest)	2m 41s
Build deltachat-rpc-server (ubuntu-latest)	2m 22s
Build deltachat-rpc-server (macos-latest)	2m 35s
Build deltachat-rpc-server (windows-latest)	19m 22s
CFFI Python tests (ubuntu-latest, 3.13)	6m 28s
CFFI Python tests (macos-latest, 3.13)	4m 54s
CFFI Python tests (ubuntu-latest, pypy3.10)	6m 49s
CFFI Python tests (macos-latest, pypy3.10)	5m 6s
CFFI Python tests (ubuntu-latest, 3.8)	4m 33s
JSON-RPC Python tests (ubuntu-latest, 3.13)	1m 45s
JSON-RPC Python tests (macos-latest, 3.13)	1m 48s
JSON-RPC Python tests (windows-latest, 3.13)	2m 48s
JSON-RPC Python tests (ubuntu-latest, pypy3.10)	2m 23s
JSON-RPC Python tests (macos-latest, pypy3.10)	2m 2s
JSON-RPC Python tests (ubuntu-latest, 3.8)	2m 16s
	1h 33m 51s

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