[Pylint] dedent should never have a number

[lmazuel]

See for instance this:

azure-sdk-for-python/sdk/tables/azure-data-tables/azure/data/tables/_table_service_client.py

Lines 84 to 89 in 93a7b3f

	.. literalinclude:: ../samples/sample_authentication.py
	:start-after: [START auth_from_connection_string]
	:end-before: [END auth_from_connection_string]
	:language: python
	:dedent: 8
	:caption: Authenticating a TableServiceClient from a connection_string

If dedent has a number, this forces a specific number of dedent, which creates possibly invalid doc:

But a number is actually optional, and if we don't put it, Sphinx dedent automatically correctly (I tested that myself with tox and sphinx).

Linter rule is to forbid people from putting a number after dedent, so sphinx can handle this by itself.

Ref: https://www.sphinx-doc.org/en/master/usage/restructuredtext/directives.html#directive-option-literalinclude-dedent

[l0lawrence]