doc(B024): #14455 add annotated but unassgined class variables

[cmp0xff]

Summary

Closes #14455, migrated from https://github.com/astral-sh/docs/pull/106.

Test Plan

Updating the documentation probably does not need a test.

[github-actions[bot]]

ruff-ecosystem results

Linter (stable)

ℹ️ ecosystem check detected linter changes. (+2 -2 violations, +0 -0 fixes in 2 projects; 52 projects unchanged)

DisnakeDev/disnake (+1 -1 violations, +0 -0 fixes)

- disnake/app_commands.py:468:7: B024 `ApplicationCommand` is an abstract base class, but it has no abstract methods
+ disnake/app_commands.py:468:7: B024 `ApplicationCommand` is an abstract base class, but it has no abstract methods or properties

apache/airflow (+1 -1 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --output-format concise --no-preview --select ALL

- airflow/secrets/base_secrets.py:26:7: B024 `BaseSecretsBackend` is an abstract base class, but it has no abstract methods
+ airflow/secrets/base_secrets.py:26:7: B024 `BaseSecretsBackend` is an abstract base class, but it has no abstract methods or properties

Changes by rule (1 rules affected)

| code | total | + violation | - violation | + fix | - fix | | ---- | ------- | --------- | -------- | ----- | ---- | | B024 | 4 | 2 | 2 | 0 | 0 |

Linter (preview)

ℹ️ ecosystem check detected linter changes. (+2 -2 violations, +0 -0 fixes in 2 projects; 52 projects unchanged)

DisnakeDev/disnake (+1 -1 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --output-format concise --preview

- disnake/app_commands.py:468:7: B024 `ApplicationCommand` is an abstract base class, but it has no abstract methods
+ disnake/app_commands.py:468:7: B024 `ApplicationCommand` is an abstract base class, but it has no abstract methods or properties

apache/airflow (+1 -1 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --output-format concise --preview --select ALL

- airflow/secrets/base_secrets.py:26:7: B024 `BaseSecretsBackend` is an abstract base class, but it has no abstract methods
+ airflow/secrets/base_secrets.py:26:7: B024 `BaseSecretsBackend` is an abstract base class, but it has no abstract methods or properties

Changes by rule (1 rules affected)

| code | total | + violation | - violation | + fix | - fix | | ---- | ------- | --------- | -------- | ----- | ---- | | B024 | 4 | 2 | 2 | 0 | 0 |

Formatter (stable)

✅ ecosystem check detected no format changes.

Formatter (preview)

✅ ecosystem check detected no format changes.

[MichaReiser]

@dylwil3 it's fine to merge documentation changes because we rarely mention them in the changelog :sweat_smile: