Updated breaking changes section (#6119)

Closes #5574

Following this Git issue:
https://github.com/orgs/dbt-labs/projects/14/views/35?pane=issue&itemId=65030468,
i've created this PR regarding the updated breaking changes

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---------

Co-authored-by: Matt Shaver <[email protected]>
Co-authored-by: Leona B. Campbell <[email protected]>
Co-authored-by: Doug Beatty <[email protected]>

website/docs/docs/collaborate/govern/model-contracts.md

@@ -206,9 +206,12 @@ At the same time, for models with many columns, we understand that this can mean
 When comparing to a previous project state, dbt will look for breaking changes that could impact downstream consumers. If breaking changes are detected, dbt will present a contract error. 
 
 Breaking changes include:
-- Removing an existing column
-- Changing the `data_type` of an existing column
-- Removing or modifying one of the `constraints` on an existing column (dbt v1.6 or higher)
+- Removing an existing column.
+- Changing the `data_type` of an existing column.
+- Removing or modifying one of the `constraints` on an existing column (dbt v1.6 or higher).
+- Removing a contracted model by deleting, renaming, or disabling it (dbt v1.9 or higher).
+  - versioned models will raise an error.
+  - unversioned models will raise a warning.
 
 More details are available in the [contract reference](/reference/resource-configs/contract#detecting-breaking-changes).