add(alloydbomni): info on compatibility with postgresql (#525)

docs/products/alloydbomni.md

@@ -11,7 +11,7 @@ Aiven for AlloyDB Omni is in the
 :::
 
 Aiven for AlloyDB Omni is a managed version of Google AlloyDB Omni purpose-built for
-mission-critical PostgreSQL workloads. It combines the power of Google's advanced database
+mission-critical PostgreSQL® workloads. It combines the power of Google's advanced database
 technology, new columnar engine, and AI capabilities with the ease of use and multi-cloud
 flexibility of the Aiven platform for Google Cloud, Amazon Web Services, and Microsoft Azure.
 
@@ -23,6 +23,10 @@ flexibility of the Aiven platform for Google Cloud, Amazon Web Services, and Mic
   applications and tools work seamlessly without requiring any code changes. It utilizes
   standard PostgreSQL drivers and supports a wide range of PostgreSQL extensions and flags.
 
+  :::note
+  Aiven for AlloyDB Omni version 15 is compatible with PostgreSQL version 15.
+  :::
+
 - High performance
 
   Experience fast transactional, analytical, and vector search workloads for real-time