Update automatic.mdx (#1133)

Updated the docs to clarify the Auto Upgrade toggle button behaviour

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Author: mibali

docs/admin/updates/automatic.mdx

@@ -1,6 +1,6 @@
 # Automatic multi-version upgrades
 
-> Warning: Automatic upgrades to v5.10.0 will fail please upgrade to a v5.9.x version and perform a standard upgrade instead! See our [postgres 12 end of life](https://sourcegraph.com/docs/admin/postgres12_end_of_life_notice#postgres-12-end-of-life) notice!
+> Warning: Automatic upgrades to v5.10.0 will fail please upgrade to a v5.9.x version and perform a standard upgrade instead! See our [postgres 12 end of life](https://sourcegraph.com/docs/admin/postgres12_end_of_life_notice#postgres-12-end-of-life) notice! This is one of the reasons the "Auto Upgrade" toggle is automatically turned off after a version change. This behavior is intentional—it’s designed to prevent users from unintentionally performing multi-version upgrades (MVUs) that span critical changes, such as major infrastructure updates like a PostgreSQL version upgrade.
 
 From **Sourcegraph 5.1 and later**, multi-version upgrades can be performed **automatically** as if they were a standard upgrade for the same deployment type. Automatic multi-version upgrades take the following general form: