Documentation appears to be incorrect for joinTable & column in many-to-many mapping

The documentation at http://gorm.grails.org/latest/hibernate/manual/index.html#_many_to_many_mapping shows how to change the column name & join table for a many-to-many relationship by creating a mapping in both classes:
```groovy
class Group {
...
static mapping = {
people column: 'Group_Person_Id',
joinTable: 'PERSON_GROUP_ASSOCIATIONS'
}
}
class Person {
...
static mapping = {
groups column: 'Group_Group_Id',
joinTable: 'PERSON_GROUP_ASSOCIATIONS'
}
}
```

This documentation seems to show that the `column` should be the ID of the other class, but it appears that it is the ID of the current class. I created a test to demonstrate this.

```groovy
class A {
Long id
String value

static hasMany = [
b: B,
]
static mapping = {
id generator: 'assigned'
b column: 'B_ID', joinTable: 'A_B'
}

static def allJoins() {
def result
withSession { session ->
def q = session.createSQLQuery("SELECT A_ID, B_ID FROM A_B")
result = q.list()
}
return result
}
}
```

```groovy
class B {
Long id
String value

static belongsTo = A
static hasMany = [
a: A,
]

static mapping = {
id generator: 'assigned'
a column: 'A_ID', joinTable: 'A_B'
}
}
```

```groovy
import grails.test.mixin.integration.Integration
import grails.transaction.Rollback
import spock.lang.Specification

@Integration
@Rollback
class ABSpec extends Specification {
void "ab join columns"() {
given:
def a1 = new A(value: 'A1')
a1.id = 101
a1.save()
def b1 = new B(value: 'B1')
b1.id = 201
b1.save()
a1.addToB(b1)
a1.save(flush: true)

expect:
A.allJoins() == [[101, 201]]
}
}
```

This test fails with the IDs in the incorrect order (the result is `[[201,101]]`)

Start with the many-to-many mapping section at the linked GORM Hibernate manual URL and compare its column and joinTable example with the A and B mappings in the issue. Run the supplied ABSpec integration test to confirm the documented column order, then update the documentation so the example matches the observed behavior.

Written by the indexing model from the issue text.