attempt to respecify dataSource

to reflect what we're actually doing with this in practice

Author: gavinking

api/src/main/java/jakarta/data/repository/Repository.java

@@ -100,14 +100,23 @@
      * Interoperability with Jakarta Config is reserved for future versions
      * of Jakarta Data.
      * </li>
-     * <li>If running in a Jakarta EE profile or platform and the entity annotations
-     * indicate a relational database and the value begins with {@code java:} and
-     * matches the name of a {@code jakarta.annotation.sql.DataSourceDefinition},
-     * the JNDI name of a data source, or a resource reference to a data source,
-     * then the corresponding {@code javax.sql.DataSource} is used as the data store.
-     * If the same conditions are met but the value matches a persistence unit
-     * reference, then the corresponding {@code jakarta.persistence.PersistenceUnit}
-     * is used as the data store.
+     * <li>In a Jakarta EE profile or platform environment, if the repository
+     * implementation requires direct access to a {@code javax.sql.DataSource}
+     * and if the value begins with {@code java:} and matches the name of a
+     * {@code jakarta.annotation.sql.DataSourceDefinition}, the JNDI name of
+     * a {@code DataSource}, or a resource reference to a {@code DataSource},
+     * then the corresponding {@code DataSource} obtained from JNDI is used.
+     * </li>
+     * <li>In a Jakarta EE profile or platform environment, if the repository
+     * implementation requires direct access to a Jakarta Persistence
+     * {@code jakarta.persistence.EntityManagerFactory} and if the value does
+     * not begin with {@code java:} and matches the name of a persistence unit,
+     * then the container-managed {@code EntityManagerFactory} for that
+     * persistence unit is used, obtained as if it had been injected using the
+     * {@code PersistenceUnit} annotation. Or, if the value does begin with
+     * {@code java:} and matches the name of a persistence unit reference,
+     * then the corresponding {@code EntityManagerFactory} obtained from JNDI
+     * is used.
      * </li>
      * <li>Otherwise, the value serves as an identifier linking to vendor-specific
      * configuration for the Jakarta Data provider to interpret in a vendor-specific