QVT — Missing association from MappingParameter to a ModelParameter

Non primitive MappingParameters are related to ModelParameters
but the the association is missing in the metamodel. Also, when
The information cannot be infered from the parameter types
there is no way to indicate this when using the textual syntax.
Suggestion:
Add the association
'MappingParameter::extent : [0..1] ModelParameter'
For the concrete syntax, use the '@' character:
mymappingparameter:MyType@mymodelparameter
Usage of this notation should not be mandatory when the model
type can be automatically infered from the parameter type.

(1) In Section 8.2.1.16 (MappingParameter) add the association:
"""
extent : ModelParameter [0..1]
The extent of the mapping parameter. Should be explicitly provided
when there is an ambiguity on the extent that will own a potential
created element corresponding to this parameter.
"""
(2) In the same section 8.2.1.16, add the "Notation" subtitle
as follows:
"""
Notation
The extent of a mapping parameter can be provided explicitly
using its name as the scope prefix of its type, using the "::"
symbol. The declarator has the form:
mymappingparameter : myextent::MyType.
It is not mandatory to provide the extent when it can be inferred
from the type.
Example:
transformation T(in src:S, out dest1, out dest2);
mapping X::foo(inout dest1::Y) : dest2:Y;
// 'X' is a class of 'S' metamodel and 'Y' is a class of 'D' metamodel
"""
Remark: No changes are needed in the grammar since the 'declarator' rule
already supports this syntax.

(3) In Figure 8.1, add the correspond link between MappingParameter
and ModelParameter.

(4) In Section 8.2.1 (ObjectExp), within the "Notation" subtitle,
replace:
"""When provided the model parameter is notated within brackets
after the object keyword.
object[srcmodel] x:X

// x is created within the 'srcmodel
"""
(this change is required for consistency with mapping parameter notation).

(5) In Section 8.2.2.23 (InstantiationExp), within the "Notation" subtitle,
replace:
"""
When provided the extent is notated by adding the variable name in brackets after the new keyword.
column := new [mymodel] Column(n,t); // mymodel is the extent for the new instance.
"""

by:
"""When an explicit extent is provided, the variable name
prefixes the type of the instantiation expression using the "::" symbol.
column := new mymodel::Column(n,t); // mymodel is the extent for the new instance.
"""