use sqlalchemy module name not engine. fixes #922

[mjuarez]

Description

Bug fix for module name emitted by sqlalchemy.

Other instrumentation libraries appear to be calling get_tracer with __name__ but the API docs seems to recommend against this.

Fixes #922

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Added test cases for instrumentation_scope.name

Does This PR Require a Core Repo Change?

• Yes. - Link to PR:
• No.

Checklist:

See contributing.md for styleguide, changelog guidelines, and more.

• Followed the style guidelines of this project
• Changelogs have been updated
• Unit tests have been added
• Documentation has been updated

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• ✅ login: mjuarez / name: Mike Juarez (acf1d1f, 512fca2, 08d3823)

[srikanthccv]

Other instrumentation libraries appear to be calling get_tracer with __name__ but the API docs seems to recommend against this.

Where it is used, it's just a single file and there is no difference b/w __name__ and having a const opentelemetry.instrumentation.x. And that might not be the case for some instrumentations so we added the explanation in the doc.