Backward incompatible changes reference for 2.3.2, 2.2.9, 2.1.18

[dshevtsov]

Purpose of this pull request

This pull request adds auto-generated reference documentation about backward incompatible changes introduced in the 2.3.2, 2.2.9, 2.1.18 versions.

Affected DevDocs pages

• https://devdocs.magento.com/guides/v2.1/release-notes/backward-incompatible-changes/reference.html

Additional information

Internal ticket: MAGEDOC-3791

whatsnew
Updated backward incompatible changes reference with the changes introduced into 2.3.2, 2.2.9, 2.1.18.

[magento-cicd2]

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1 out of 2 committers have signed the CLA.

✅ dshevtsov
❌ magento-team

[dshevtsov]

running tests

[ghost]

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