Using own Feature - constant for "delete with returning"

[gitmotte]

#1527 introduced DELETE with RETURNING and used Feature.insertReturningExpressionList
within the validation net.sf.jsqlparser.util.validation.validator.DeleteValidator - the Feature.insertReturningExpressionList is part of the validation group FeaturesAllowed.INSERT and therefore only allowed for INSERT statements.

The bugfix fixes the problem with a new feature constant Feature.deleteReturningExpressionList which is part of the validation group FeaturesAllowed.DELETE.

[manticore-projects]

Thank you for helping me out! I honestly have no idea how this validation framework works and tried brute force.

[gitmotte]

Are the correlations clearer for you now, when you look at the changes?

[gitmotte]

I've added a "Further development" section to the wiki of my fork - could you please merge it to the original wiki of JSQLParser @wumpz ?

https://github.com/gitmotte/JSqlParser/wiki/Examples-of-SQL-Validation#further-development

(don't know how to add merge requests for wiki-pages)

[wumpz]

merged it :) manually