Fix malformed docstring for rolemap.importRolemap

[stevepiercy]

The docstring was malformed and invalid, resulting in Sphinx build errors in the main Plone documentation.

Plone/documentation/venv/lib/python3.13/site-packages/Products/GenericSetup/rolemap.py:docstring of Products.GenericSetup.rolemap.importRolemap:9: ERROR: Unexpected indentation. [docutils]
Plone/documentation/venv/lib/python3.13/site-packages/Products/GenericSetup/rolemap.py:docstring of Products.GenericSetup.rolemap.importRolemap:19: WARNING: Definition list ends without a blank line; unexpected unindent. [docutils]

This PR fixes the docstrings, adding proper lexers. Now it looks purty.

See screenshot.

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Refs: plone/documentation#2083 (review)

When merged, and docs are rebuilt in that PR, then preview the final result at https://plone6--2083.org.readthedocs.build/backend/generic-setup.html#Products.GenericSetup.rolemap.importRolemap

[stevepiercy]

If it's not too much effort, would you please create a release so that we can publish these changes? Thank you!

[dataflake]

Version 5.2 is now released