[Documentation] Adding "versionadded" (#6336)

|      Q       |   A
|------------- | -----------
| Type         | improvement
| Fixed issues | none

#### Summary

Page:
https://www.doctrine-project.org/projects/doctrine-dbal/en/4.0/reference/types.html#bigint

The `int`-mapping needs to be added at
https://www.doctrine-project.org/projects/doctrine-orm/en/3.1/reference/basic-mapping.html#doctrine-mapping-types
too!

What is the right version information? Is it only working if you have
DBAL 4 **and** ORM 3?

docs/en/reference/types.rst

@@ -91,6 +91,10 @@ Values retrieved from the database are always converted to PHP's ``integer`` typ
 if they are within PHP's integer range or ``string`` if they aren't.
 Otherwise, returns ``null`` if no data is present.
 
+.. versionadded:: 4.0
+
+The mapping to PHP `int` was added in version 4.0
+
 .. note::
 
     Due to architectural differences, 32-bit PHP systems have a smaller