[lang] Make localized the messages related to forbidden and discouraged references

see #232
see #259

Signed-off-by: Stéphane Galland <galland@arakhne.org>
[lang] Put the annotation ImportedCapacityFeature into the generated code.

The `ImportedCapacityFeature` is used for marking the operations that
are imported with the "uses" keyword.

see #102

Signed-off-by: Stéphane Galland <galland@arakhne.org>
[lang] Output a warning when a capacity is not used.

see #102

Signed-off-by: Stéphane Galland <galland@arakhne.org>
[lang][ui] Add quick fix for the unused capacities.

see #102

Signed-off-by: Stéphane Galland <galland@arakhne.org>
[lang][core] Apply code style.

Signed-off-by: Stéphane Galland <galland@arakhne.org>